qpnp: pwm: Amend the LPG enable sequence

The LPG enable control register needs to be written
first before we write to ramp control register. The driver
currently does it in the reverse order right now. Amend the
order.

CRs-Fixed: 484327
Change-Id: I4ea0627e3bdf2ce840f5ce60cc8c63f034f146af
Signed-off-by: Jay Chokshi <jchokshi@codeaurora.org>