microblaze: Remove unused prom header from reset.c

Completely unused header by this file.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/kernel/reset.c

@@ -9,7 +9,6 @@
 
 #include <linux/init.h>
 #include <linux/of_platform.h>
-#include <asm/prom.h>
 
 /* Trigger specific functions */
 #ifdef CONFIG_GPIOLIB