Revert "Input: do not pass injected events back to the originating handler"

This reverts commit 5fdbe44d033d059cc56c2803e6b4dbd8cb4e5e39.

Apparently there exist userspace programs that expect to be able to
"loop back" and distribute to readers events written into
/dev/input/eventX and this change made for the benefit of SysRq
handler broke them. Now that SysRq uses alternative method to suppress
filtering of the events it re-injects we can safely revert this change.

Reported-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>