Add libfabric patch: log efa_is_local_peer GID decisions

Patches efa_conn.c to always log (at WARN level) whether each peer
is classified as LOCAL or REMOTE based on GID comparison. This will
show definitively whether remote peers are being misidentified as
local (causing messages to be routed through SHM where they fail).

Author: Sbozzolo

spack_repo/patches/efa_local_peer_debug.diff

@@ -0,0 +1,37 @@
+--- prov/efa/src/efa_conn.c.orig	2026-07-13 16:22:58
++++ prov/efa/src/efa_conn.c	2026-07-13 16:23:15
+@@ -15,23 +15,25 @@
+ {
+ 	int i;
+ 	uint8_t *raw_gid = ((struct efa_ep_addr *)addr)->raw;
++	char peer_gid_str[INET6_ADDRSTRLEN] = { 0 };
++	char local_gid_str[INET6_ADDRSTRLEN] = { 0 };
+ 
+-#if ENABLE_DEBUG
+-	char raw_gid_str[INET6_ADDRSTRLEN] = { 0 };
++	inet_ntop(AF_INET6, raw_gid, peer_gid_str, INET6_ADDRSTRLEN);
+ 
+-	if (!inet_ntop(AF_INET6, raw_gid, raw_gid_str, INET6_ADDRSTRLEN)) {
+-		EFA_WARN(FI_LOG_AV, "Failed to get current EFA's GID, errno: %d\n", errno);
+-		return 0;
+-	}
+-	EFA_INFO(FI_LOG_AV, "The peer's GID is %s.\n", raw_gid_str);
+-#endif
+ 	for (i = 0; i < g_efa_ibv_gid_cnt; ++i) {
+ 		if (!memcmp(raw_gid, g_efa_ibv_gid_list[i].raw, EFA_GID_LEN)) {
+-			EFA_INFO(FI_LOG_AV, "The peer is local.\n");
++			inet_ntop(AF_INET6, g_efa_ibv_gid_list[i].raw,
++				  local_gid_str, INET6_ADDRSTRLEN);
++			EFA_WARN(FI_LOG_AV,
++				 "efa_is_local_peer: MATCH peer=%s == local[%d]=%s -> LOCAL\n",
++				 peer_gid_str, i, local_gid_str);
+ 			return 1;
+ 		}
+ 	}
+ 
++	EFA_WARN(FI_LOG_AV,
++		 "efa_is_local_peer: NO MATCH peer=%s (checked %d local GIDs) -> REMOTE\n",
++		 peer_gid_str, g_efa_ibv_gid_cnt);
+ 	return 0;
+ }
+