sb/intel: Fix pointer casts

Fix some compiler warnings due to pointer to integer conversions
with different size.
Required for 64bit ramstage.

Change-Id: Ibfb3cacf25adfb4a242d38e4ea290fdc3929a684
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/c/29875
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/southbridge/intel/i82801ix/lpc.c

@@ -553,7 +553,7 @@ static void southbridge_inject_dsdt(struct device *dev)
 
 		/* Add it to SSDT.  */
 		acpigen_write_scope("\\");
-		acpigen_write_name_dword("NVSA", (u32) gnvs);
+		acpigen_write_name_dword("NVSA", (uintptr_t)gnvs);
 		acpigen_pop_len();
 	}
 }