Revert "ANDROID: net: xfrm: check dir value of xfrm_userpolicy_id"

This is fixed in a much cleaner way in 7bab0963 ("xfrm: policy:
check policy direction value"). There is no point to having all of
these extra checks when the one will do.

This reverts commit 33f17703.

Bug: 64257838
Change-Id: I9c5862cdf1da9934144d1f785de6d2c3e69d0dd7
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>