ARM: bcm: fix missing include of kona_l2_cache.h

Fix a warning of kona_l2_cache_init() not being declared by
including the header file kona_l2_cache.h which defines it
thus fixing:

arch/arm/mach-bcm/kona_l2_cache.c:21:13: warning: symbol 'kona_l2_cache_init' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Acked-by: NRay Jui <ray.jui@broadcom.com>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>

arch/arm/mach-bcm/kona_l2_cache.c

@@ -17,6 +17,7 @@
 #include <asm/hardware/cache-l2x0.h>
 
 #include "bcm_kona_smc.h"
+#include "kona_l2_cache.h"
 
 void __init kona_l2_cache_init(void)
 {