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/include/linux/pim.h b/include/linux/pim.h
index 252bf66..e1d756f 100644
--- a/include/linux/pim.h
+++ b/include/linux/pim.h
@@ -13,6 +13,11 @@
 
 #define PIM_NULL_REGISTER	cpu_to_be32(0x40000000)
 
+static inline bool ipmr_pimsm_enabled(void)
+{
+	return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
+}
+
 /* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
 struct pimreghdr
 {