Rename CONFIG_PWM to CONFIG_PWM_S5P and move to Kconfig

We rename the S5P specific "CONFIG_PWM" to CONFIG_PWM_S5P and move it to
Kconfig.  Given the usage of CONFIG_PWM_NX, we have that select this new
symbol.

Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index cb54e67..8fd5a2e 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -84,6 +84,11 @@
 	  useful. The PWM can be enabled but is not connected to any outputs
 	  so this is not very useful.
 
+config PWM_S5P
+	bool "Enable non-DM support for S5P PWM"
+	depends on (S5P || ARCH_NEXELL)
+	default y
+
 config PWM_SIFIVE
 	bool "Enable support for SiFive PWM"
 	depends on DM_PWM