soc/amd/sabrina/Kconfig: update SOC_AMD_COMMON_BLOCK_UCODE_SIZE

The Sabrina microcode update files are 3200 bytes large and not 5568
like it is the case on Cezanne where this file was originally copied
from.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I12209d523096781195ba8957ec797d8c80eecbe5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63127
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/sabrina/Kconfig

@@ -87,7 +87,7 @@ config ARCH_ALL_STAGES_X86
 	default n
 
 config SOC_AMD_COMMON_BLOCK_UCODE_SIZE
-	default 5568
+	default 3200
 
 config CHIPSET_DEVICETREE
 	string