drivers: pwm: Infineon: PWM driver improvements and bug fixes

This change makes improvements and bug fixes for the Infineon PWM
driver.  These include:

* Removes hard coded register addresss from driver.
* Addresses issues causing pwm_api and pwm_gpio_loopback tests to
fail, as well as functional failures.
* Restructures device tree file to better represent the hardware
architecture of the tcpwm module.
* Allows configuration of hardware behavior when PWM is disabled.

Signed-off-by: Bill Waters <bill.waters@infineon.com>