src/mainboard/kahlee: Default AMD FW position to 1MB

For Kahlee, the AMD firmware directory should be in the 1MB location
so that it's in the RO cbfs section.

BUG=b:65484600
TEST=Build & boot

Change-Id: I650d8bc0bfa773f5fb5dc11167fe3db3b9550b68
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/22003
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/kahlee/Kconfig

@@ -70,4 +70,8 @@ config GBB_HWID
 	depends on CHROMEOS
 	default "KAHLEE TEST 6421"
 
+config AMD_FWM_POSITION_INDEX
+	int
+	default 1
+
 endif # BOARD_GOOGLE_KAHLEE