Add support for %z in tf_print()
Add support for %z in tf_print()

Add support for %z format specific in tf_printf() to support
printing data of type size_t

Fixes ARM-software/tf-issues#380

Signed-off-by Scott Branden <scott.branden@broadcom.com>

sbranden/arm-trusted-firmware,achingupta/arm-trusted-firmware,lsigithub/arm-trusted-firmware_public,sandrine-bailleux/arm-trusted-firmware,sandrine-bailleux-arm/arm-trusted-firmware,sbranden/arm-trusted-firmware,achingupta/arm-trusted-firmware,lsigithub/arm-trusted-firmware_public,sandrine-bailleux-arm/arm-trusted-firmware,sandrine-bailleux/arm-trusted-firmware