scripts/checkpatch.pl: Don't allow special cases of unspaced operators

The checkpatch.pl script has a special case to permit the following
operators to have no spaces around them:
 <<  >>  &  ^  |  +  -  *  /  %

QEMU style prefers all operators to consistently have spacing around
them, so remove this special case handling. This avoids reviewers
having to manually note it during code review.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
