lib_manager: check context allocation on dram restore

The resume path allocated a library context and immediately wrote
through it without a NULL check, crashing under memory pressure. Check
the allocation and fail the restore gracefully.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Author: lrgirdwo

src/library_manager/llext_manager_dram.c

@@ -200,10 +200,14 @@ int llext_manager_restore_from_dram(void)
 			continue;
 		}
 
-		/* Panics on failure - use the same zone as during the first boot */
 		struct lib_manager_mod_ctx *ctx = rmalloc(SOF_MEM_FLAG_KERNEL | SOF_MEM_FLAG_COHERENT,
 							  sizeof(*ctx));
 
+		if (!ctx) {
+			tr_err(&lib_manager_tr, "library context allocation failure");
+			goto nomem;
+		}
+
 		/* Restore the library context */
 		*ctx = lib_manager_dram.ctx[j++];