x86/microcode/intel: Rename mc_intel variable to mc

x86/microcode/intel: Rename mc_intel variable to mc

Well, it is apparent what it points to - microcode. And since it is the
intel loader, no need for the "_intel" suffix. Use "!" for the 0/NULL
checks, while at it.

No functionality change.

Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1454499225-21544-10-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>