led: remove camel casing of led identifiers globally

Result of running the following command to address Wolfgang's
comment about camel case:

for file in `find . | grep '\.[chS]$'`; do perl -i -pe
's/(green|yellow|red|blue)_LED_(on|off)/$1_led_$2/g' $file; done

Discussion:
http://patchwork.ozlabs.org/patch/84988/



Signed-off-by: Jason Kridner <jkridner@beagleboard.org>
Signed-off-by: Joel A Fernandes <agnel.joel@gmail.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>