ARM: pxa: delete the custom GPIO header

The PXA sub-architecture appears to have a custom <mach/gpio.h>
for no reason whatsoever. The file became completely empty
after Haojian removed the remaining content in
commit 157d2644
"ARM: pxa: change gpio to platform device".

That commit added these two lines:

However it seems like deleting the file has no effect
whatsoever on the kernel compilation.

Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/Kconfig

@@ -621,7 +621,6 @@ config ARCH_PXA
 	select GPIO_PXA
 	select HAVE_IDE
 	select MULTI_IRQ_HANDLER
-	select NEED_MACH_GPIO_H
 	select PLAT_PXA
 	select SPARSE_IRQ
 	help

arch/arm/mach-pxa/include/mach/gpio.h

-/*
- * arch/arm/mach-pxa/include/mach/gpio.h
- *
- * PXA GPIO wrappers for arch-neutral GPIO calls
- *
- * Written by Philipp Zabel <philipp.zabel@gmail.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- */
-
-#ifndef __ASM_ARCH_PXA_GPIO_H
-#define __ASM_ARCH_PXA_GPIO_H
-
-#include <asm-generic/gpio.h>
-
-#include <mach/irqs.h>
-#include <mach/hardware.h>
-
-#endif