soc: xilinx: zynqmp: Mark soc_xilinx_zynqmp_get_machine() as static

Fix the following sparse and compile time warning triggered with W=1:

drivers/soc/soc_xilinx_zynqmp.c:288:5:
warning: no previous prototype for 'soc_xilinx_zynqmp_get_machine'
[-Wmissing-prototypes]

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20221004055201.26146-1-venkatesh.abbarapu@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/drivers/soc/soc_xilinx_zynqmp.c b/drivers/soc/soc_xilinx_zynqmp.c
index c10fc7d..a51bcdb 100644
--- a/drivers/soc/soc_xilinx_zynqmp.c
+++ b/drivers/soc/soc_xilinx_zynqmp.c
@@ -285,7 +285,7 @@
 	return snprintf(buf, size, "%s", priv->family);
 }
 
-int soc_xilinx_zynqmp_get_machine(struct udevice *dev, char *buf, int size)
+static int soc_xilinx_zynqmp_get_machine(struct udevice *dev, char *buf, int size)
 {
 	struct soc_xilinx_zynqmp_priv *priv = dev_get_priv(dev);
 	const char *machine = priv->machine;