build: Build fs_get_stats even for TINY_ANDROID

We need fs_get_stats if we're using u-boot because it's used
during tarball creation.
Build it even for TINY_ANDROID (unless TARGET_BOOTLOADER_TYPE == fastboot)

Change-Id: If9ed3b63699b9f6c04a08b7b131a00b3a856c946
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>