fix(intel): define macros to handle buffer entries

This patch defines a macro to handle Secure Device Manager's (SDM)
pointer to command & response buffer entries and convert them to the
correct physical address.

Signed-off-by: Abdul Halim, Muhammad Hadi Asyrafi <muhammad.hadi.asyrafi.abdul.halim@intel.com>
Change-Id: I4cf9f1d90e0d5ae4e1a2ce84165864b48c2862e7