soc/amd/picasso,stoneyridge/acpi: drop x_firmware_ctl_[l,h] assignment

The coreboot-common acpi_create_fadt writes a pointer to the FACS table
into both firmware_ctrl and x_firmware_ctl_l FADT fields and sets
x_firmware_ctl_h to zero. When x_firmware_ctl_[l,h] is non-zero, the
pointer in firmware_ctrl will be ignored, but that's what is already
done on Cezanne and newer.

TEST=Linux doesn't complain about any new ACPI problem on Mandolin.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ib9eab4dcf828f28a60c6312ec96872aac4cfb266
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73190
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
diff --git a/src/soc/amd/picasso/acpi.c b/src/soc/amd/picasso/acpi.c
index 125aa0a..081ed10 100644
--- a/src/soc/amd/picasso/acpi.c
+++ b/src/soc/amd/picasso/acpi.c
@@ -99,9 +99,6 @@
 			ACPI_FADT_S4_RTC_VALID |
 			ACPI_FADT_REMOTE_POWER_ON;
 	fadt->flags |= cfg->fadt_flags; /* additional board-specific flags */
-
-	fadt->x_firmware_ctl_l = 0;	/* set to 0 if firmware_ctrl is used */
-	fadt->x_firmware_ctl_h = 0;
 }
 
 static uint32_t get_pstate_core_freq(msr_t pstate_def)
diff --git a/src/soc/amd/stoneyridge/acpi.c b/src/soc/amd/stoneyridge/acpi.c
index 40976af..bc3e73a 100644
--- a/src/soc/amd/stoneyridge/acpi.c
+++ b/src/soc/amd/stoneyridge/acpi.c
@@ -90,9 +90,6 @@
 				ACPI_FADT_PLATFORM_CLOCK |
 				ACPI_FADT_S4_RTC_VALID |
 				ACPI_FADT_REMOTE_POWER_ON;
-
-	fadt->x_firmware_ctl_l = 0;	/* set to 0 if firmware_ctrl is used */
-	fadt->x_firmware_ctl_h = 0;
 }
 
 void generate_cpu_entries(const struct device *device)