qpnp: pwm: Remove LUT mode dependency of PWM driver

Some low cost Qualcomm pmic chipsets such as PM8110 do not
have LUT slice in their PWM module. In the existing PWM driver
design, it does not probe if LUT base address is not provided
in device tree. PMICs that do not support LUT mode do not have
LUT base address populated, which is perfectly fine.

Thus, remove the requirement to always have LUT base address
present and check if LUT mode is supported during operations that
involve LUT mode.

CRs-Fixed: 490081
Change-Id: Ie705172b21d13120cf96781840c3cc6ef4160851
Signed-off-by: Jay Chokshi <jchokshi@codeaurora.org>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>