mei: fix potential read outside of array bounds

Drop not-very-useful check and with this
fix read on index that can be after array end.
Cleanup search function as byproduct.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>