This patch removes the need for a shared buffer between the EL3 and S-EL1
levels. We now use the CPU registers, x0-x7, while passing data between
the two levels. Since TLK is a 32-bit Trusted OS, tlkd has to unpack the
arguments in the x0-x7 registers. TLK in turn gets these values via r0-r7.
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>