net: fealnx: fix build for UML

[ Upstream commit cd2621d07d517473611b170c69beb6524c677740 ]

On i386, when builtin (not a loadable module), the fealnx driver
inspects boot_cpu_data to see what CPU family it is running on, and
then acts on that data. The "family" struct member (x86) does not exist
when running on UML, so prevent that test and do the default action.

Prevents this build error on UML + i386:

../drivers/net/ethernet/fealnx.c: In function ‘netdev_open’:
../drivers/net/ethernet/fealnx.c:861:19: error: ‘struct cpuinfo_um’ has no member named ‘x86’

Fixes: 68f5d3f3b6 ("um: add PCI over virtio emulation driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-um@lists.infradead.org
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://lore.kernel.org/r/20211014050500.5620-1-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/ethernet/fealnx.c

@@ -857,7 +857,7 @@ static int netdev_open(struct net_device *dev)
 	np->bcrvalue |= 0x04;	/* big-endian */
 #endif
 
-#if defined(__i386__) && !defined(MODULE)
+#if defined(__i386__) && !defined(MODULE) && !defined(CONFIG_UML)
 	if (boot_cpu_data.x86 <= 4)
 		np->crvalue = 0xa00;
 	else