net: ag71xx: add COMPILE_TEST to test compilation

While this driver is meant for MIPS only, it can be compiled on x86 just
fine. Remove pointless parentheses while at it.

Enables CI building of this driver.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240905194938.8453-2-rosenp@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/atheros/Kconfig

@@ -6,7 +6,7 @@
 config NET_VENDOR_ATHEROS
 	bool "Atheros devices"
 	default y
-	depends on (PCI || ATH79)
+	depends on PCI || ATH79 || COMPILE_TEST
 	help
 	  If you have a network (Ethernet) card belonging to this class, say Y.
 
@@ -19,7 +19,7 @@ if NET_VENDOR_ATHEROS
 
 config AG71XX
 	tristate "Atheros AR7XXX/AR9XXX built-in ethernet mac support"
-	depends on ATH79
+	depends on ATH79 || COMPILE_TEST
 	select PHYLINK
 	imply NET_SELFTESTS
 	help