net: phy: fix yt8511 clang uninitialized variable warning

clang doesn't preinitialize variables. If phy_select_page failed and
returned an error, phy_restore_page would be called with `ret` being
uninitialized.
Even though phy_restore_page won't use `ret` in this scenario,
initialize `ret` to silence the warning.

Fixes: 48e8c6f1 ("net: phy: add driver for Motorcomm yt8511 phy")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/motorcomm.c

@@ -50,8 +50,8 @@ static int yt8511_write_page(struct phy_device *phydev, int page)
 
 static int yt8511_config_init(struct phy_device *phydev)
 {
+	int oldpage, ret = 0;
 	unsigned int ge, fe;
-	int ret, oldpage;
 
 	/* set clock mode to 125mhz */
 	oldpage = phy_select_page(phydev, YT8511_EXT_CLK_GATE);