oprofile, x86: Fix wrapping bug in op_x86_get_ctrl()

commit 44009105081b51417f311f4c3be0061870b6b8ed upstream.

The "event" variable is a u16 so the shift will always wrap to zero
making the line a no-op.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>