Use <linux/fscrypt.h> from Bionic

aosp/1184798 has updated the kernel headers to 5.4, so we no longer need
the file fscrypt_uapi.h.  In KeyUtil.cpp we also now don't need
<linux/fs.h>, but rather just the more specific <linux/fscrypt.h>.

Test: build
Bug: None
Change-Id: I56d17826eb7c3b95c74ce0435a4feae7f3cc325e
2 files changed