x86: coding style fixes to arch/x86/xen/multicalls.c

Before:
   total: 2 errors, 2 warnings, 138 lines checked
After:
   total: 0 errors, 2 warnings, 138 lines checked

No code changed:

arch/x86/xen/multicalls.o:

   text	   data	    bss	    dec	    hex	filename
    887	   2832	      0	   3719	    e87	multicalls.o.before
    887	   2832	      0	   3719	    e87	multicalls.o.after

md5:
   cf6d72d9db6dc5a3ebe01eec9f05e95f  multicalls.o.before.asm
   cf6d72d9db6dc5a3ebe01eec9f05e95f  multicalls.o.after.asm

Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>