apple/macbook21: Remove useless seabios config

Change-Id: If771a84f25710e1fb2228816e3ca0139e2f95aa7
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6732
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/mainboard/apple/macbook21/Kconfig

@@ -59,8 +59,4 @@ config MAINBOARD_SMBIOS_MANUFACTURER
 	string
 	default "Apple Inc."
 
-config SEABIOS_PS2_TIMEOUT
-	int
-	default 3000
-
 endif