[ARM] Cleanup ARM includes

arch/arm/kernel/entry-armv.S has contained a comment suggesting
that asm/hardware.h and asm/arch/irqs.h should be moved into the
asm/arch/entry-macro.S include.  So move the includes to these
two files as required.

Add missing includes (asm/hardware.h, asm/io.h) to asm/arch/system.h
includes which use those facilities, and remove asm/io.h from
kernel/process.c.

Remove other unnecessary includes from arch/arm/kernel, arch/arm/mm
and arch/arm/mach-footbridge.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/process.c

@@ -28,10 +28,9 @@
 #include <linux/init.h>
 #include <linux/cpu.h>
 
-#include <asm/system.h>
-#include <asm/io.h>
 #include <asm/leds.h>
 #include <asm/processor.h>
+#include <asm/system.h>
 #include <asm/uaccess.h>
 #include <asm/mach/time.h>