zynqmp: Add support to provide silicon id through SMC

Add support to provide silicon id to non-secure
software through SMC.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>

[ sb
Move zynqmp_get_silicon_id outside of compile guards to avoid build
errors.
]

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/plat/xilinx/zynqmp/zynqmp_private.h b/plat/xilinx/zynqmp/zynqmp_private.h
index ddef37b..abcdebc 100644
--- a/plat/xilinx/zynqmp/zynqmp_private.h
+++ b/plat/xilinx/zynqmp/zynqmp_private.h
@@ -39,6 +39,7 @@
 unsigned int zynqmp_get_uart_clk(void);
 int zynqmp_is_pmu_up(void);
 unsigned int zynqmp_get_bootmode(void);
+unsigned int zynqmp_get_silicon_id(void);
 
 /* For FSBL handover */
 void fsbl_atf_handover(entry_point_info_t *bl32_image_ep_info,