phy: pistachio-usb: Depend on MIPS || COMPILE_TEST

So it will be avilable for generic MIPS kernel.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

drivers/phy/Kconfig

@@ -37,7 +37,7 @@ config PHY_LPC18XX_USB_OTG
 
 config PHY_PISTACHIO_USB
 	tristate "IMG Pistachio USB2.0 PHY driver"
-	depends on MACH_PISTACHIO
+	depends on MIPS || COMPILE_TEST
 	select GENERIC_PHY
 	help
 	  Enable this to support the USB2.0 PHY on the IMG Pistachio SoC.