net: evaluate net.ipv4.conf.all.proxy_arp_pvlan

Introduced in 65324144, the "proxy_arp_vlan" sysctl is a
per-interface sysctl to tune proxy ARP support for private VLANs.
While the "all" variant is exposed, it was a noop and never evaluated.
We use the usual "or" logic for this kind of sysctls.

Fixes: 65324144 ("net: RFC3069, private VLAN proxy arp support")
Signed-off-by: Vincent Bernat <vincent@bernat.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/inetdevice.h

@@ -105,7 +105,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
 
 #define IN_DEV_LOG_MARTIANS(in_dev)	IN_DEV_ORCONF((in_dev), LOG_MARTIANS)
 #define IN_DEV_PROXY_ARP(in_dev)	IN_DEV_ORCONF((in_dev), PROXY_ARP)
-#define IN_DEV_PROXY_ARP_PVLAN(in_dev)	IN_DEV_CONF_GET(in_dev, PROXY_ARP_PVLAN)
+#define IN_DEV_PROXY_ARP_PVLAN(in_dev)	IN_DEV_ORCONF((in_dev), PROXY_ARP_PVLAN)
 #define IN_DEV_SHARED_MEDIA(in_dev)	IN_DEV_ORCONF((in_dev), SHARED_MEDIA)
 #define IN_DEV_TX_REDIRECTS(in_dev)	IN_DEV_ORCONF((in_dev), SEND_REDIRECTS)
 #define IN_DEV_SEC_REDIRECTS(in_dev)	IN_DEV_ORCONF((in_dev), \