mb/google/brya: Fix MAINBOARD_PART_NUMBER

This change updates MAINBOARD_PART_NUMBER string to use uppercase for
first character. This matches what all others boards do.

BUG=b:180456030

Change-Id: I10eaeef5ec662a5718b787a3f0e3705cf70d751d
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51297
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/brya/Kconfig b/src/mainboard/google/brya/Kconfig
index 17dab64..a23156f 100644
--- a/src/mainboard/google/brya/Kconfig
+++ b/src/mainboard/google/brya/Kconfig
@@ -61,7 +61,7 @@
 
 config MAINBOARD_PART_NUMBER
 	string
-	default "brya" if BOARD_GOOGLE_BRYA0
+	default "Brya" if BOARD_GOOGLE_BRYA0
 
 config VARIANT_DIR
 	string