On the imx6dl-yapp4 revision based boards, the RGB LED is not driven
directly by the LP5562 driver but through FET transistors. Hence the LED
current is not determined by the driver but by the LED series resistors.

On the imx6dl-yapp43 revision based boards, we removed the FET transistors
to drive the LED directly from the LP5562 but forgot to tune the output
current to match the previous HW design.

Set the LED current on imx6dl-yapp43 based boards to the same values
measured on the imx6dl-yapp4 boards and limit the maximum current to 20mA.

Fixes: 7da47347 ("ARM: dts: imx6dl-yapp43: Add support for new HW revision of the IOTA board")
Cc: <stable@vger.kernel.org>
Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>