serial: tegra: Fix compilation error

Fix compilation error, by adding the correct header file
for Tegra clocks.
Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

@@ -43,7 +43,7 @@
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 
-#include <mach/clk.h>
+#include <linux/clk/tegra.h>
 
 #define TEGRA_UART_TYPE				"TEGRA_UART"
 #define TX_EMPTY_STATUS				(UART_LSR_TEMT | UART_LSR_THRE)