net: gem: Add driver dependencies to PHYLIB

Clear driver dependecies via Kconfig. Remove PHYLIB dependency from
the driver.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index e77797a..ae5e78d 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -103,6 +103,7 @@
 
 config ZYNQ_GEM
 	depends on DM_ETH && (ARCH_ZYNQ || ARCH_ZYNQMP)
+	select PHYLIB
 	bool "Xilinx Ethernet GEM"
 	help
 	  This MAC is present in Xilinx Zynq and ZynqMP SoCs.
diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
index f7c20dc..7059c84 100644
--- a/drivers/net/zynq_gem.c
+++ b/drivers/net/zynq_gem.c
@@ -27,10 +27,6 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#if !defined(CONFIG_PHYLIB)
-# error XILINX_GEM_ETHERNET requires PHYLIB
-#endif
-
 /* Bit/mask specification */
 #define ZYNQ_GEM_PHYMNTNC_OP_MASK	0x40020000 /* operation mask bits */
 #define ZYNQ_GEM_PHYMNTNC_OP_R_MASK	0x20000000 /* read operation */