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/arch/arm/cpu/arm946es/cpu.c b/arch/arm/cpu/arm946es/cpu.c
index 8523a97..fb0ea5e 100644
--- a/arch/arm/cpu/arm946es/cpu.c
+++ b/arch/arm/cpu/arm946es/cpu.c
@@ -15,6 +15,7 @@
 #include <common.h>
 #include <command.h>
 #include <cpu_func.h>
+#include <irq_func.h>
 #include <asm/system.h>
 #include <asm/io.h>