PM: Remove unused asm/suspend.h

This patch removes unused asm/suspend.h files for
the following architectures:

 alpha, arm, ia64, m68k, mips, s390, um

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>