mba4,2: Remove USBDEBUG_HCD_INDEX.

MBa doesn't have a usable usbdebug port.

Change-Id: Ia8459daa5c9b9405c289954b28ecf1423b1f076c
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/11849
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>

src/mainboard/apple/macbookair4_2/Kconfig

@@ -59,8 +59,4 @@ config DRAM_RESET_GATE_GPIO
 config MAX_CPUS
 	int
 	default 8
-
-config USBDEBUG_HCD_INDEX # FIXME: check this
-	int
-	default 2
 endif