uart: The uart.h header file uses uint32_t without including stdint.h.

Make it include stdint.h instead of relying on that file having already been
included by something else.

BUG=None
TEST=Built for link, lumpy, nyan, pit.
BRANCH=None

Change-Id: Ia09abc890a5f6b12318aa4ae0897aa8a0baf3b13
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://chromium-review.googlesource.com/171335
Reviewed-by: Ronald Minnich <rminnich@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
diff --git a/src/include/uart.h b/src/include/uart.h
index 9601bfa..cd62c6d 100644
--- a/src/include/uart.h
+++ b/src/include/uart.h
@@ -26,6 +26,8 @@
 #ifndef UART_H
 #define UART_H
 
+#include <stdint.h>
+
 #if CONFIG_CONSOLE_SERIAL8250 || CONFIG_CONSOLE_SERIAL8250MEM
 #include <uart8250.h>
 #endif