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>

arch/arm/mach-omap2/hdq1w.c

@@ -27,6 +27,7 @@
 #include <linux/err.h>
 #include <linux/platform_device.h>
 
+#include "soc.h"
 #include "omap_hwmod.h"
 #include "omap_device.h"
 #include "hdq1w.h"
@@ -93,4 +94,4 @@ static int __init omap_init_hdq(void)
 
 	return 0;
 }
-arch_initcall(omap_init_hdq);
+omap_arch_initcall(omap_init_hdq);