msm: HTC: fighter: clean-up ack_err_status after lcd_on

This clean-up function is present in the lcd_on functions of both
mipi_novatek.c and HTC's 3.0.8 source.

Change-Id: Idec4433870be6f977aedc53b7b1da7c8a70be00d
msm: HTC: fighter: use mipi_dsi_cmds_tx for backlight commands

Change-Id: I518d87fdd88138b877deeb2e7633058e4798c508
msm: HTC: fighter: only send backlight commands when appropriate

Disregard backlight adjustments while the display is off or when
there is no change in level.

Change-Id: Iaede60d0a649a9f33b752790fc35e4ebdd7fcdad