x86/ucode: Don't try to cope with NULL pointers in apply_microcode()

x86/ucode: Don't try to cope with NULL pointers in apply_microcode()

No paths to apply_microcode() pass a NULL pointer, and other hooks don't
tolerate one in the first place.  We can expect the core logic not to pass us
junk, so drop the checks.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>