powerpc/ima: Drop unnecessary check for CONFIG_MODULE_SIG

powerpc/ima: Drop unnecessary check for CONFIG_MODULE_SIG

When CONFIG_MODULE_SIG is disabled set_module_sig_enforced() is defined
as an empty stub, so the check is unnecessary.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>