leds: lm3532: Fix brightness control for i2c mode

Fix the brightness control for I2C mode.  Instead of
changing the full scale current register update the ALS target
register for the appropriate banks.

In addition clean up some code errors and random misspellings found
during coding.

Tested on Droid4 as well as LM3532 EVM connected to a BeagleBoneBlack

Fixes: bc1b8492 ("leds: lm3532: Introduce the lm3532 LED driver")
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>