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/configs/tec_defconfig b/configs/tec_defconfig
index 9ba3062..274fc9d 100644
--- a/configs/tec_defconfig
+++ b/configs/tec_defconfig
@@ -15,6 +15,7 @@
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_TEGRA=y
 CONFIG_SYS_NS16550=y
 CONFIG_USB=y
 CONFIG_DM_USB=y