Revert "perf: Fix perf_event_validate_size()"

This reverts commit ebc7597c which is
commit 382c27f4 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I7db90bfbe74a408b807480c811382e38731f0c53
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>