mb/google/brya: Define a more suitable MRC training text message

This message is designed to reduce end-user confusion who may not
know what memory training is. It also provides a maximum time
estimation calibrated for brya devices.

BUG=b:252792591
BRANCH=firmware-brya-14505.B
TEST=New message observed on skolas

Change-Id: Ie71cd86746427789b3694d41224bf2c170af0f91
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70796
Reviewed-by: Anil Kumar K <anil.kumar.k@intel.com>
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/brya/Kconfig

@@ -332,4 +332,7 @@ config PCIEXP_DEFAULT_MAX_RESIZABLE_BAR_BITS
 	int
 	default 32
 
+config MEMORY_TRAINING_TEXT
+	default "Your device is finishing an update. This may take 1-2 minutes.\\Please do not turn off your device."
+
 endif # BOARD_GOOGLE_BRYA_COMMON