Fix mkexfatfs exclusion when TW_NO_EXFAT enabled

Push to android-5.0

Conflicts:
	Android.mk

Change-Id: I0b831a4e6e52e4b314751035b750e6a398cb4d2d
crypto: fix build in < 5.0 tree

Change-Id: Ie4ed3e91cfb7e509bac1d6db885bd3f415d2b168