x86: clean up i387.c

minor coding style cleanups.

Before:
   total: 0 errors, 3 warnings, 479 lines checked
After:
   total: 0 errors, 1 warnings, 483 lines checked

No code changed:

arch/x86/kernel/i387.o:

   text	   data	    bss	    dec	    hex	filename
   2379	      4	      8	   2391	    957	i387.o.before
   2379	      4	      8	   2391	    957	i387.o.after

md5:
   e1434553a3b4ff1f52ad97a68b1fad8a  i387.o.before.asm
   e1434553a3b4ff1f52ad97a68b1fad8a  i387.o.after.asm

Signed-off-by: Ingo Molnar <mingo@elte.hu>