arm64: tegra: Populate Tegra234 PWMs

Populate all the PWM devices for Tegra234. Finally, update the
compatible string for the existing 'pwm1' node to just be 'tegra194-pwm'
and remove the fallback to 'tegra186-pwm', which aligns with the
binding documentation.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>