current code only works because struct uart_port
is the first member on the uart_omap_port structure.

If, for whatever reason, someone puts another
member as the first of the structure, that cast
won't work anymore. In order to be safe, let's use
a container_of() which, for now, gets optimized into
a cast anyway.

Tested-by: Shubhrajyoti D <redacted>
Acked-by: Santosh Shilimkar <redacted>
Signed-off-by: Felipe Balbi <redacted>
---
 arch/arm/plat-omap/include/plat/omap-serial.h |  2 ++
 drivers/tty/serial/omap-serial.c              | 36 +++++++++++++--------------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h
index 1a52725..f3b35d9 100644
--- a/arch/arm/plat-omap/include/plat/omap-serial.h
+++ b/arch/arm/plat-omap/include/plat/omap-serial.h

@@ -137,4 +137,6 @@ struct uart_omap_port {
 	struct work_struct	qos_work;
 };
 
+#define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
+
 #endif /* __OMAP_SERIAL_H__ */