ARM: OMAP2+: Use omap initcalls

This way the initcalls don't run on other SoCs on multiplatform
kernels. Otherwise we'll get something like this when booting
on vexpress:

omap_hwmod: _ensure_mpu_hwmod_is_setup: MPU initiator hwmod mpu not yet registered
...
WARNING: at arch/arm/mach-omap2/pm.c:82 _init_omap_device+0x74/0x94()
_init_omap_device: could not find omap_hwmod for mpu
...
omap-dma-engine omap-dma-engine: OMAP DMA engine driver
...

Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/gpio.c b/arch/arm/mach-omap2/gpio.c
index 399acab..40950f5 100644
--- a/arch/arm/mach-omap2/gpio.c
+++ b/arch/arm/mach-omap2/gpio.c
@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/platform_data/gpio-omap.h>
 
+#include "soc.h"
 #include "omap_hwmod.h"
 #include "omap_device.h"
 #include "omap-pm.h"
@@ -147,7 +148,7 @@
 /*
  * gpio_init needs to be done before
  * machine_init functions access gpio APIs.
- * Hence gpio_init is a postcore_initcall.
+ * Hence gpio_init is a omap_postcore_initcall.
  */
 static int __init omap2_gpio_init(void)
 {
@@ -157,4 +158,4 @@
 
 	return omap_hwmod_for_each_by_class("gpio", omap2_gpio_dev_init, NULL);
 }
-postcore_initcall(omap2_gpio_init);
+omap_postcore_initcall(omap2_gpio_init);