disas/s390.c: Remove unused variables

The variables s390_opformats and s390_num_opformats are unused and
provoke clang warnings:

disas/s390.c:849:33: warning: variable 's390_opformats' is not needed and will not be emitted [-Wunneeded-internal-declaration]
static const struct s390_opcode s390_opformats[] =
                                ^
disas/s390.c:875:18: warning: unused variable 's390_num_opformats' [-Wunused-const-variable]
static const int s390_num_opformats =
                 ^

Delete them, since QEMU doesn't use them.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Message-id: 1419373100-17690-3-git-send-email-peter.maydell@linaro.org
Signed-off-by: Richard Henderson <rth@twiddle.net>