phy: ralink: Kconfig: enable COMPILE_TEST on mt7621-pci-phy driver

After use the clock apis and avoid custom architecture
code this driver can properly be enabled for COMPILE_TEST.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>

drivers/phy/ralink/Kconfig

@@ -4,7 +4,7 @@
 #
 config PHY_MT7621_PCI
 	tristate "MediaTek MT7621 PCI PHY Driver"
-	depends on RALINK && OF
+	depends on (RALINK && OF) || COMPILE_TEST
 	select GENERIC_PHY
 	select REGMAP_MMIO
 	help