hw/drivers/pwm: Add ISR tracing for nRF52 PWM driver
hw/drivers/pwm: Add ISR tracing for nRF52 PWM driver

This requires small wrappers around nrfx ISR handlers to add tracing
code, but these are added only if sysview is enabled.

mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core