phy: xilinx: phy-zynqmp: mention SGMII as supported protocol

SGMII is validated on kria KR260 robotics starter kit. So modify the
comment description to include it in supported controllers list.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/1679940407-13131-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/xilinx/phy-zynqmp.c

@@ -8,9 +8,8 @@
  * Author: Subbaraya Sundeep <sundeep.lkml@gmail.com>
  * Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  *
- * This driver is tested for USB, SATA and Display Port currently.
+ * This driver is tested for USB, SGMII, SATA and Display Port currently.
- * Other controllers PCIe and SGMII should also work but that is
+ * PCIe should also work but that is experimental as of now.
- * experimental as of now.
  */
 
 #include <linux/clk.h>