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/cmd/irq.c b/cmd/irq.c
index bcc718b..52d06b3 100644
--- a/cmd/irq.c
+++ b/cmd/irq.c
@@ -6,6 +6,7 @@
 #include <common.h>
 #include <config.h>
 #include <command.h>
+#include <irq_func.h>
 
 static int do_interrupts(cmd_tbl_t *cmdtp, int flag, int argc,
 			 char * const argv[])