ARM: dts: msm: Specify HR_LED configuration for PM855B

Homerow LEDs (HR_LED) are present on PM855B which can be used
on sdm855 platforms. Add the required configuration for it.

Change-Id: I46140d3ed8ebdde4d1377449e3deed9e849f3dac
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>