For chip drivers that support both pwm and non-pwm modes would encounter compilation errors if the platform doesn't have support for pwm though the chip is programmed to work in non-pwm mode. Add __weak attributed pwm functions to avoid compilation issues in these scenarios. Change-Id: I6affff1ced9c84aefa3962b94780fd3e50ee1c35 Signed-off-by: Mohan Pallaka <mpallaka@codeaurora.org> (cherry picked from commit f056d9e5cfbd376a266c1db32c271d0f3ad0319b)