stmmac: dwmac-loongson: Add architecture dependency

Only present the DWMAC_LOONGSON option on architectures where it can
actually be used.

This follows the same logic as the DWMAC_INTEL option.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -280,7 +280,7 @@ config DWMAC_INTEL
 config DWMAC_LOONGSON
 	tristate "Loongson PCI DWMAC support"
 	default MACH_LOONGSON64
-	depends on STMMAC_ETH && PCI
+	depends on (MACH_LOONGSON64 || COMPILE_TEST) && STMMAC_ETH && PCI
 	depends on COMMON_CLK
 	help
 	  This selects the LOONGSON PCI bus support for the stmmac driver,