ANDROID: fscrypt: fix export symbol type

In commit d16d9c0046eb ("FROMLIST: fscrypt: Have filesystems handle their d_ops")
a new symbol was exported, but it should have been set as a _GPL symbol.

Fix this up by properly.

Bug: 138322712
Cc: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I51e23761d3c898a0bf612048c8febd98a0817ae3