common: Move enable/disable_interrupts out of common.h

Move these two functions into the irq_funcs.h header file. Also move
interrupt_handler_t as this is used by the irq_install_handler() function.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/pic32_flash.c b/drivers/mtd/pic32_flash.c
index 8f09e5b..8fff818 100644
--- a/drivers/mtd/pic32_flash.c
+++ b/drivers/mtd/pic32_flash.c
@@ -10,6 +10,7 @@
 #include <dm.h>
 #include <fdt_support.h>
 #include <flash.h>
+#include <irq_func.h>
 #include <mach/pic32.h>
 #include <wait_bit.h>