Fix type of SMC function ID

The SMC function identifier is always a 32-bit integer, regardless of
the caller's execution state and of the SMC calling convention in use.

Change-Id: I8d4f7b9efcea3f00ac2ff0a397ca0d8ab824eecb
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/lib/smc/aarch64/smc.c b/lib/smc/aarch64/smc.c
index 06b841c..cbe4bb9 100644
--- a/lib/smc/aarch64/smc.c
+++ b/lib/smc/aarch64/smc.c
@@ -7,14 +7,14 @@
 #include <stdint.h>
 #include <tftf.h>
 
-smc_ret_values asm_tftf_smc64(u_register_t arg0,
-					u_register_t arg1,
-					u_register_t arg2,
-					u_register_t arg3,
-					u_register_t arg4,
-					u_register_t arg5,
-					u_register_t arg6,
-					u_register_t arg7);
+smc_ret_values asm_tftf_smc64(uint32_t arg0,
+			      u_register_t arg1,
+			      u_register_t arg2,
+			      u_register_t arg3,
+			      u_register_t arg4,
+			      u_register_t arg5,
+			      u_register_t arg6,
+			      u_register_t arg7);
 
 smc_ret_values tftf_smc(const smc_args *args)
 {