leds: lp55xx_common: Enable use without FW_LOADER_USER_HELPER

Many distributions disable FW_LOADER_USER_HELPER, and this configuration
makes lp55xx LEDs completely unusable. Enable their use by only implying
the user helper, since the basic LEDs and the hardware patterns can be used
with only the sysfs interface.

Tested on Nokia N900 with LP5523.

Additionally do not refer to the sysfs interface as legacy anymore, since
it might be the only one available to users.

Signed-off-by: Sicelo A. Mhlongo <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

Documentation/leds/leds-lp5521.rst

···
 LP5521 has the internal program memory for running various LED patterns.
 There are two ways to run LED patterns.
 
-1) Legacy interface - enginex_mode and enginex_load
+1) sysfs interface - enginex_mode and enginex_load
    Control interface for the engines:
 
    x is 1 .. 3

Documentation/leds/leds-lp5523.rst

···
 LP5523 has the internal program memory for running various LED patterns.
 There are two ways to run LED patterns.
 
-1) Legacy interface - enginex_mode, enginex_load and enginex_leds
+1) sysfs interface - enginex_mode, enginex_load and enginex_leds
 
   Control interface for the engines:
 

drivers/leds/Kconfig

···
 	depends on LEDS_CLASS_MULTICOLOR
 	depends on OF
 	depends on I2C
-	select FW_LOADER
-	select FW_LOADER_USER_HELPER
+	imply FW_LOADER
+	imply FW_LOADER_USER_HELPER
 	help
 	  This option supports common operations for LP5521/5523/55231/5562/5569/
 	  8501 devices.