tegra: Convert CONFIG_PWM_TEGRA to Kconfig

Move this option to Kconfig and clean up the header files. Adjust the only
user (the LCD driver) to work with the new driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index cd8f357..e5880ac 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -17,3 +17,11 @@
 	  programmable period and duty cycle. A 32-bit counter is used.
 	  Various options provided in the hardware (such as capture mode and
 	  continuous/single-shot) are not supported by the driver.
+
+config PWM_TEGRA
+	bool "Enable support for the Tegra PWM"
+	help
+	  This PWM is found on Tegra 20 and other Nvidia SoCs. It supports
+	  four channels with a programmable period and duty cycle. Only a
+	  32KHz clock is supported by the driver but the duty cycle is
+	  configurable.