SDEI: Fix build error with logging enabled

Change-Id: Iee617a3528225349b6eede2f8abb26da96640678
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

services/std_svc/sdei/sdei_main.c

@@ -993,7 +993,7 @@ uint64_t sdei_smc_handler(uint32_t smc_fid,
 	case SDEI_PE_UNMASK:
 		SDEI_LOG("> UNMASK:%lx\n", read_mpidr_el1());
 		sdei_pe_unmask();
-		SDEI_LOG("< UNMASK:%ld\n", 0);
+		SDEI_LOG("< UNMASK:%d\n", 0);
 		SMC_RET1(handle, 0);
 		break;