x86 PM: rename 32-bit files in arch/x86/power

Rename cpu.c, suspend.c and swsusp.S in arch/x86/power to cpu_32.c,
hibernate_32.c and hibernate_asm_32.S, respectively, and update the
purpose and copyright information in these files.

Update the Makefile in arch/x86/power to reflect the above changes.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>