Fix pointer type mismatch of handlers

Commit 4c0d03907652 ("Rework type usage in Trusted Firmware") changed
the type usage in struct declarations, but did not touch the definition
side.  Fix the type mismatch.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/plat/nvidia/tegra/common/tegra_sip_calls.c b/plat/nvidia/tegra/common/tegra_sip_calls.c
index d96ce7a..a818453 100644
--- a/plat/nvidia/tegra/common/tegra_sip_calls.c
+++ b/plat/nvidia/tegra/common/tegra_sip_calls.c
@@ -49,14 +49,14 @@
 /*******************************************************************************
  * This function is responsible for handling all SiP calls
  ******************************************************************************/
-uint64_t tegra_sip_handler(uint32_t smc_fid,
-			   uint64_t x1,
-			   uint64_t x2,
-			   uint64_t x3,
-			   uint64_t x4,
-			   void *cookie,
-			   void *handle,
-			   uint64_t flags)
+uintptr_t tegra_sip_handler(uint32_t smc_fid,
+			    u_register_t x1,
+			    u_register_t x2,
+			    u_register_t x3,
+			    u_register_t x4,
+			    void *cookie,
+			    void *handle,
+			    u_register_t flags)
 {
 	uint32_t regval;
 	int err;