mb/google/bluey: Increase bootblock size to 120KB

The bootblock size for the Google Bluey mainboard has been increased
from 96KB to 120KB.

This change is necessary to accommodate the growing size of the
bootblock image, which now exceeds the previous 96KB limit. This
expansion ensures that the complete bootblock code, including critical
initialization routines and potentially new features, fits within its
allocated flash region.

TEST=Able to build google/quenbi.

Change-Id: I7bf2c8c6c540327f1b4233ee5ba4e0703d1200f9
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87903
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/bluey/chromeos.fmd

@@ -3,7 +3,7 @@
 FLASH@0x0 CONFIG_ROM_SIZE {
 	WP_RO 4M {
 		RO_SECTION 0x3c4000 {
-			BOOTBLOCK 96K
+			BOOTBLOCK 120K
 			COREBOOT(CBFS)
 			FMAP@0x3c0000 0x1000
 			GBB 0x2f00