mb/google/rex: Move `DRIVERS_INTEL_USB4_RETIMER` config

This patch moves DRIVERS_INTEL_USB4_RETIMER config from Meteor Lake
SoC to Rex mainboard to maintain the symmetry with previous
generation ChromeOS devices (Brya and Volteer).

BUG=none
TEST=Able to build and boot to Google/Rex with USB4 functionality
remaining intact.

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I38360f6f1f2fcb4b0315de93c68f00d77e63003c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68771
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
diff --git a/src/mainboard/google/rex/Kconfig b/src/mainboard/google/rex/Kconfig
index b56fd58..ebdc2aa 100644
--- a/src/mainboard/google/rex/Kconfig
+++ b/src/mainboard/google/rex/Kconfig
@@ -4,6 +4,7 @@
 	select DRIVERS_GENERIC_MAX98357A
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_I2C_HID
+	select DRIVERS_INTEL_USB4_RETIMER
 	select DRIVERS_SOUNDWIRE_ALC5682
 	select DRIVERS_WIFI_GENERIC
 	select DRIVERS_INTEL_MIPI_CAMERA