x86, mce: trivial clean up for mce.c

This fixs following checkpatch warnings:

WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
+#include <asm/uaccess.h>

WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>
+#include <asm/smp.h>

WARNING: line over 80 characters
+                               set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog.flags);

WARNING: braces {} are not necessary for any arm of this statement
+       if (mce_notify_user()) {
[...]
+       } else {
[...]

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>