ANDROID: sdcardfs: get rid of 'parent' argument of ->d_compare()

->d_compare() doesn't get parent as a separate argument anymore
according to upstream commit 6fa67e70 ("get rid of 'parent'
argument of ->d_compare()").

We run into following build error otherwise:

  CC [M]  fs/sdcardfs/dentry.o
fs/sdcardfs/dentry.c:183:15: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
  .d_compare = sdcardfs_cmp_ci,
               ^
fs/sdcardfs/dentry.c:183:15: note: (near initialization for ‘sdcardfs_ci_dops.d_compare’)

Change-Id: I51801b57aeb8287f1e69ce6cb944e8722ff37bea
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>