net: ipmr: move pimsm_enabled to pim.h and rename

Move the inline pimsm_enabled() to pim.h and rename it to
ipmr_pimsm_enabled to show it's for the ipv4 ipmr code since pim.h is
used by IPv6 too.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index ff3dbbb..322fdc6 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -75,11 +75,6 @@
 	struct mr_table		*mrt;
 };
 
-static inline bool pimsm_enabled(void)
-{
-	return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
-}
-
 /* Big lock, protecting vif table, mrt cache and mroute socket state.
  * Note that the changes are semaphored via rtnl_lock.
  */
@@ -751,7 +746,7 @@
 
 	switch (vifc->vifc_flags) {
 	case VIFF_REGISTER:
-		if (!pimsm_enabled())
+		if (!ipmr_pimsm_enabled())
 			return -EINVAL;
 		/* Special Purpose VIF in PIM
 		 * All the packets will be sent to the daemon
@@ -1377,7 +1372,7 @@
 		mrt->mroute_do_assert = val;
 		break;
 	case MRT_PIM:
-		if (!pimsm_enabled()) {
+		if (!ipmr_pimsm_enabled()) {
 			ret = -ENOPROTOOPT;
 			break;
 		}
@@ -1451,7 +1446,7 @@
 		val = 0x0305;
 		break;
 	case MRT_PIM:
-		if (!pimsm_enabled())
+		if (!ipmr_pimsm_enabled())
 			return -ENOPROTOOPT;
 		val = mrt->mroute_do_pim;
 		break;