cmd: Add a pwm command

Add the command "pwm" for controlling the pwm channels. This
command provides pwm invert/config/enable/disable functionalities
via PWM uclass drivers

Signed-off-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 1b53e5b..0625ee4 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -928,6 +928,12 @@
 	help
 	  GPIO support.
 
+config CMD_PWM
+	bool "pwm"
+	depends on DM_PWM
+	help
+	  Control PWM channels, this allows invert/config/enable/disable PWM channels.
+
 config CMD_GPT
 	bool "GPT (GUID Partition Table) command"
 	select EFI_PARTITION