x86: add ENDPROC() markers

The ENDPROCs() were not used everywhere.  Some code used just END() instead,
while other code used nothing.  um/sys-i386/checksum.S didn't #include
<linux/linkage.h> .  I also got confused because gcc puts the
.type near the ENTRY, while ENDPROC puts it on the opposite end.

Signed off by: John Reiser <jreiser@BitWagon.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>