ARM64: zynqmp: Remove unneeded timer_init function

Empty weak function is used instead.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/board/xilinx/zynqmp/zynqmp.c b/board/xilinx/zynqmp/zynqmp.c
index ac23625..1a83789 100644
--- a/board/xilinx/zynqmp/zynqmp.c
+++ b/board/xilinx/zynqmp/zynqmp.c
@@ -57,11 +57,6 @@
 	return 0;
 }
 
-int timer_init(void)
-{
-	return 0;
-}
-
 void reset_cpu(ulong addr)
 {
 }