regulator: Fix 88pm8607.c printk format warning

Fix printk format warning (seen on x86_64) and change to unsigned
output format:

drivers/regulator/88pm8607.c:417: warning: format '%d' expects type 'int', but argument 3 has type 'resource_size_t'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>