backlight/ld9040.c: regulator control in the driver

This patch supports regulator power control in the driver.
Current ld9040 driver was controlled power on/off sequence by callback function in the board file. But, by doing this, there's no need to register lcd power on/off callback function in the board file.

changes since v2:
- bind regulators as bulk data
- in case of failure to get regulator, free regulator bulk data

---
 drivers/video/backlight/ld9040.c |   71
+++++++++++++++++++++++++++++++------
 1 files changed, 59 insertions(+), 12 deletions(-)

b/drivers/video/backlight/ld9040.c
index da9a5ce..133ddff 100644

*spi)
ld9040_power(lcd, FB_BLANK_POWERDOWN);
backlight_device_unregister(lcd->bd);
lcd_device_unregister(lcd->ld);
+ regulator_bulk_free(ARRAY_SIZE(supplies), supplies);
kfree(lcd);

return 0;

1.7.4.1