ARM: mach-shmobile: fix compile warning in mm/init.c

Turn down the warning noise from the compiler,
basically a SH-Mobile specific version of the
patch located in the RMK patch tracker:

6484/1: "fix compile warning in mm/init.c",

Without this patch the following warning triggers:

 CC      arch/arm/kernel/sys_arm.o
arch/arm/mm/init.c: In function 'mem_init':
arch/arm/mm/init.c:606: warning: format '%08lx' expects type 'long unsigned int', but argument 12 has type 'unsigned int'
  CC      arch/arm/kernel/traps.o

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>