hikey960.mk: install sdcardfs.ko into the ramdisk

to make the sdcardfs feature work.

Test: cts-tradefed could run with device information collected
      sdcardfs mountpoints listed in the mount command output

Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Change-Id: I62d30b6e2bcf28fcaf2baebdc7caa96c4c2f9a47
1 file changed