[POWERPC] Include <asm/mmu.h> in arch/powerpc/sysdev/fsl_soc.h for phys_addr_t.

This patch causes fsl_soc.h to import the definition of phys_addr_t
itself, rather than relying on its includer to do so.
Signed-off-by: Scott Wood <scott@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/sysdev/fsl_soc.h

@@ -2,6 +2,8 @@
 #define __PPC_FSL_SOC_H
 #ifdef __KERNEL__
 
+#include <asm/mmu.h>
+
 extern phys_addr_t get_immrbase(void);
 
 #endif