mb/google/brox: Add romstage early graphics

Select MAINBOARD_USE_EARLY_LIBGFXINIT for brox to enable SOL image.
This patch enables Sign of Life image during MRC training.

BUG=b:335369811
TEST=Able to boot to ChromeOS with SOL image.

CPU log:
[SPEW ]  bootmode is set to: 0 (boot with full config)
[0.384818] DP PHY mode status not complete
[0.388911] DP PHY mode status not complete
[0.393197] DP PHY mode status not complete
[0.397484] DP PHY mode status not complete
[0.401771] DP PHY mode status not complete
[0.406057] DP PHY mode status not complete
[0.410345] DP PHY mode status not complete
[0.414632] DP PHY mode status not complete
[0.418916] DP PHY mode status not complete
[0.423203] DP PHY mode status not complete
[0.427491] DP PHY mode status not complete
[0.431777] DP PHY mode status not complete
[INFO ]  Informing user on-display of memory training.
[DEBUG]  FMAP: area COREBOOT found @ 1877000 (7901184 bytes)
[WARN ]  CBFS: 'preram_locales' not found.
[ERROR]  ux_locales_get_text: preram_locales not found.
[DEBUG]  FMAP: area RW_ELOG found @ f20000 (16384 bytes)
[INFO ]  ELOG: NV offset 0xf20000 size 0x4000

elogtool list:
0 | 2024-05-10 02:26:07-0700 | Log area cleared | 4088
1 | 2024-05-10 02:26:07-0700 | Early Sign of Life | MRC Early SOL Screen Shown
2 | 2024-05-10 02:26:51-0700 | Memory Cache Update | Normal | Success
3 | 2024-05-10 02:27:09-0700 | System boot | 4
4 | 2024-05-10 02:27:09-0700 | Firmware Splash Screen | Enabled
5 | 2024-05-10 02:27:11-0700 | System Reset
6 | 2024-05-10 02:27:11-0700 | Firmware vboot info | boot_mode=Developer | fw_tried=A | fw_try_count=0 | fw_prev_tried=A | fw_prev_result=Unknown
7 | 2024-05-10 02:27:18-0700 | ACPI Enter | S5
8 | 2024-05-10 02:27:36-0700 | System boot | 5
9 | 2024-05-10 02:27:36-0700 | Firmware Splash Screen | Enabled
10 | 2024-05-10 02:27:37-0700 | System Reset
11 | 2024-05-10 02:27:37-0700 | Firmware vboot info | boot_mode=Developer | fw_tried=A | fw_try_count=0 | fw_prev_tried=A | fw_prev_result=Unknown


Change-Id: I1d4795825960bc58f8f7ef494b01aa975f3bc346
Signed-off-by: Sowmya Aralguppe <sowmya.aralguppe@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81931
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Shelley Chen <shchen@google.com>
Reviewed-by: Ashish Kumar Mishra <ashish.k.mishra@intel.com>
diff --git a/src/mainboard/google/brox/Kconfig b/src/mainboard/google/brox/Kconfig
index 00a0509..2637e89 100644
--- a/src/mainboard/google/brox/Kconfig
+++ b/src/mainboard/google/brox/Kconfig
@@ -52,6 +52,7 @@
 	select SOC_INTEL_COMMON_BLOCK_HDA_VERB
 	select SOC_INTEL_TCSS_USE_PDC_PMC_USBC_MUX_CONFIGURATION
 	select DRIVERS_INTEL_ISH
+	select MAINBOARD_HAS_EARLY_LIBGFXINIT
 	select SYSTEM_TYPE_LAPTOP
 	select TPM_GOOGLE_TI50