LM3556 :
The LM3556 is a 4 MHz fixed-frequency synchronous boost
converter plus 1.5A constant current driver for a high-current white LED.
Datasheet: www.national.com/ds/LM/LM3556.pdf

Tested on OMAP4430

(bryan.wu@canonical.com: use module_i2c_driver() rather than
lm3556_init/lm3556_exit for code simplicity; fixed some typo
pointed out by Rob Landley)
Signed-off-by: NG.Shark Jeong <gshark.jeong@gmail.com>
Reviewed-by: NAxel Lin <axel.lin@gmail.com>
Reviewed-by: NKim, Milo <Milo.Kim@ti.com>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NBryan Wu <bryan.wu@canonical.com>