fix(intel): fix ddr address range checker

This patch fix address range checker to make sure that it does not
errors out on NULL address with size 0. Non-secure software will send
this NULL address if the SMC call doesn't need to pass any address buffer.

Signed-off-by: Abdul Halim, Muhammad Hadi Asyrafi <muhammad.hadi.asyrafi.abdul.halim@intel.com>
Change-Id: I7e492c562a311ba989570c4ed465f845333ec865