ARM: dts: msm: Keep WLED disabled in pmi8998

Keep WLED device disabled in pmi8998. It needs to be enabled in
the board files with proper string configuration without which
there could be a possible HW damage.

Change-Id: I64491ffa051ef28733f7fd4abca1693c0a0f1eee
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>