for compatible 32bit and 64bit, we use 0x82xxxxxx as function ID,
we modify SIP call function return value to 32 bit.

Change-Id: Ib99b03a9ea423853aaa296dcc634ee82c622a552

add auto_pd_dis_freq parameter, we can pass a frequency from kernel
to disable or enable ddr auto power down function.

Change-Id: Ie30914701336c59047c380381c6b75dd76a89562

add dram driver, and kernel can through sip function talk to bl31 to
do ddr frequency scaling. and ddr auto powerdown.

Change-Id: I0d0f2869aed95e336c6e23ba96a9310985c84840