ns16550: change map_sysmem to map_physmem

Change map_sysmem() to map_physmem(,,MAP_NOCACHE). Though map_sysmem()
can be used to map system memory, it might be wrong to use it for I/O
ports.  The map_physmem() serves the same purpose to translate physical
address to virtual address with the additional flag to take care of cache
property. Most drivers use map_physmem() since I/O ports access should be
uncached. As ns16550 is a driver, it should use map_physmem() rather
than map_sysmem().

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/serial/ns16550.c

@@ -8,7 +8,6 @@
 #include <dm.h>
 #include <errno.h>
 #include <fdtdec.h>
-#include <mapmem.h>
 #include <ns16550.h>
 #include <serial.h>
 #include <watchdog.h>
@@ -97,7 +96,7 @@ static void ns16550_writeb(NS16550_t port, int offset, int value)
 	unsigned char *addr;
 
 	offset *= 1 << plat->reg_shift;
-	addr = map_sysmem(plat->base, 0) + offset;
+	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
 	/*
 	 * As far as we know it doesn't make sense to support selection of
 	 * these options at run-time, so use the existing CONFIG options.
@@ -111,7 +110,7 @@ static int ns16550_readb(NS16550_t port, int offset)
 	unsigned char *addr;
 
 	offset *= 1 << plat->reg_shift;
-	addr = map_sysmem(plat->base, 0) + offset;
+	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
 
 	return serial_in_shift(addr, plat->reg_shift);
 }