samples: fade_led: change hard-coded device name

Use the config name defined by the driver Kconfig in device
binding calls as that is more portable and safer because device
name can change and the app does not need to change.

Jira: ZEP-1764

Change-Id: I3287da5c5a9df24507efa84bbf7bbb051726bc2c
Signed-off-by: Kuo-Lang Tseng <[email protected]>

Author: kltseng

samples/basic/fade_led/src/main.c

@@ -16,14 +16,16 @@
 #include <pwm.h>
 
 #if defined(CONFIG_SOC_STM32F401XE) || defined(CONFIG_SOC_STM32L476XX)
-#define PWM_DRIVER "PWM_2"
+#define PWM_DRIVER CONFIG_PWM_STM32_2_DEV_NAME
 #define PWM_CHANNEL 1
 #elif CONFIG_SOC_STM32F103XB
-#define PWM_DRIVER "PWM_1"
+#define PWM_DRIVER CONFIG_PWM_STM32_1_DEV_NAME
 #define PWM_CHANNEL 1
-#else
-#define PWM_DRIVER "PWM_0"
+#elif defined(CONFIG_SOC_QUARK_SE_C1000) || defined(CONFIG_SOC_QUARK_D2000)
+#define PWM_DRIVER CONFIG_PWM_QMSI_DEV_NAME
 #define PWM_CHANNEL 0
+#else
+#error "Choose supported PWM driver"
 #endif
 
 /*