mtd: fix the build warning for fsl_upm.c

Fix the build warning:

drivers/mtd/nand/fsl_upm.c: In function 'fun_chip_init':
drivers/mtd/nand/fsl_upm.c:190: warning: format '%x' expects type 'unsigned int', but argument 3 has type 'resource_size_t'

Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>