x86: irq_64.c fix style problems

Impact: cleanup, fix style problems, more readable

Fix:

 WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
 WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>
 ERROR: code indent should use tabs where possible

 total: 9 errors, 2 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>