zynqmp: pm: Implement pinctrl request/release EEMI API
zynqmp: pm: Implement pinctrl request/release EEMI API

The calls are just passed through to the PMU-FW. Before issuing
other pinctrl functions the pin should be successfully requested.

Signed-off-by: Mirela Simonovic <789a56bf0be082732c408d9b08112674350ff427@aggios.com>
Signed-off-by: Rajan Vaja <958387e48e282671f29716c1b482329c5293cdb8@xilinx.com>
Change-Id: Ibce280edebedf779b3962009c274d0b3d928e0e4

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware