Allow iotrace byte access to use an address of any size

If an address is used with readb() and writeb() which is smaller than the
expected size (e.g. 32-bit value on a machine with 64-bit addresses), a
warning results. Fix this by adding a cast.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/iotrace.h

@@ -31,10 +31,11 @@
 #define writew(val, addr)	iotrace_writew(val, (const void *)(addr))
 
 #undef readb
-#define readb(addr)	iotrace_readb((const void *)(addr))
+#define readb(addr)	iotrace_readb((const void *)(uintptr_t)addr)
 
 #undef writeb
-#define writeb(val, addr)	iotrace_writeb(val, (const void *)(addr))
+#define writeb(val, addr) \
+	iotrace_writeb(val, (const void *)(uintptr_t)addr)
 
 #endif