ARM: dts: omap5-uevm: Add LED support for uEVM blue LED

Add support for blue LED 1 off of GPIO 153.
Make the LED a heartbeat LED
Configure the MUX for GPIO output.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
[r.sricharan@ti.com: Replaced constants with preprocessor macros]
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>