ARM: Fix build error for SMP=n builds

Unfortunately, the module fixups cause the kernel to fail to build
when SMP is not enabled.  Fix this by removing the reference to
fixup_smp on non-SMP fixup kernels, but ensuring that if we do have
the SMP fixup section, we refuse to load the module.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>