backlight: lcd: Add LCD_POWER_ constants for power states

backlight: lcd: Add LCD_POWER_ constants for power states

Duplicate FB_BLANK_ constants as LCD_POWER_ constants in the lcd
header file. Allows lcd drivers to avoid including the fbdev header
file and removes a compile-time dependency between the two subsystems.

The new LCD_POWER_ constants have the same values as their
FB_BLANK_ counterparts. Hence semantics does not change and the lcd
drivers can be converted one by one. Each instance of FB_BLANK_UNBLANK
becomes LCD_POWER_ON, each of FB_BLANK_POWERDOWN becomes LCD_POWER_OFF,
FB_BLANK_NORMAL becomes LCD_POWER_REDUCED and FB_BLANK_VSYNC_SUSPEND
becomes LCD_POWER_REDUCED_VSYNC_SUSPEND.

Lcd code or drivers do not use FB_BLANK_HSYNC_SUSPEND, so no
new constants for this is being added. The tokens LCD_POWER_REDUCED
and LCD_POWER_REDUCED_VSYNC_SUSPEND are deprecated and drivers should
replace them with LCD_POWER_ON and LCD_POWER_OFF.

See also commit a1cacb8a8e70 ("backlight: Add BACKLIGHT_POWER_ constants
for power states"), which added similar constants for backlight drivers.

v2:
- fix typo in commit description

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240906075439.98476-4-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>