net: fix endian check warning in etherdevice.h

Sparse builds have been warning for a really long time now
that etherdevice.h has a conversion that is unsafe.

include/linux/etherdevice.h:79:32: warning: restricted __be16 degrades to integer

This code change fixes the issue and generates the exact
same assembly before/after (checked on x86_64)

Fixes: 2c722fe1c821 (etherdevice: Optimize a few is_<foo>_ether_addr functions)
Signed-off-by: Jesse Brandeburg <[e-mail]>
CC: Joe Perches <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/etherdevice.h

···
 
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 	return (((*(const u32 *)addr) ^ (*(const u32 *)b)) |
-		((a[2] ^ b[2]) & m)) == 0;
+		(__force int)((a[2] ^ b[2]) & m)) == 0;
 #else
 	return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
 #endif