defconfig: lahaina-gki: Enable PWM LPG driver

Enable the QTI PWM LPG driver that configures PWM/LPG channels on
Qualcomm Technologies Inc. PMICs for clients such as LEDs.

Change-Id: Ic854b1b01b0769eccfc680fa961ed4107694ba28
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>