net: phy: Remove static return type for phy_device_create()

Remove static return type for phy_device_create() to avoid file scope for
this function. Also add required prototype in phy.h.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Link: https://lore.kernel.org/r/1517f4053403fbd53e899d500e7485d068a4f0b6.1645627539.git.michal.simek@xilinx.com
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index c9fc208..f63705e 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -659,9 +659,9 @@
 	return generic_for_interface(interface);
 }
 
-static struct phy_device *phy_device_create(struct mii_dev *bus, int addr,
-					    u32 phy_id, bool is_c45,
-					    phy_interface_t interface)
+struct phy_device *phy_device_create(struct mii_dev *bus, int addr,
+				     u32 phy_id, bool is_c45,
+				     phy_interface_t interface)
 {
 	struct phy_device *dev;