bsp: cvitek: switch to device init function for some drivers

Some drivers use INIT_BOARD_EXPORT, it is not necessary,
it is enough to use INIT_DEVICE_EXPORT for genearl drivers.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>

bsp/cvitek/drivers/drv_adc.c

@@ -212,4 +212,4 @@ int rt_hw_adc_init(void)
 
     return RT_EOK;
 }
-INIT_BOARD_EXPORT(rt_hw_adc_init);
+INIT_DEVICE_EXPORT(rt_hw_adc_init);

bsp/cvitek/drivers/drv_hw_i2c.c

@@ -601,4 +601,4 @@ int rt_hw_i2c_init(void)
 
     return result;
 }
-INIT_BOARD_EXPORT(rt_hw_i2c_init);
+INIT_DEVICE_EXPORT(rt_hw_i2c_init);

bsp/cvitek/drivers/drv_pwm.c

@@ -335,4 +335,4 @@ int rt_hw_pwm_init(void)
     }
     return RT_EOK;
 }
-INIT_BOARD_EXPORT(rt_hw_pwm_init);
+INIT_DEVICE_EXPORT(rt_hw_pwm_init);

bsp/cvitek/drivers/drv_spi.c

@@ -342,4 +342,4 @@ int rt_hw_spi_init(void)
 
     return ret;
 }
-INIT_BOARD_EXPORT(rt_hw_spi_init);
+INIT_DEVICE_EXPORT(rt_hw_spi_init);

bsp/cvitek/drivers/drv_wdt.c

@@ -167,4 +167,4 @@ int rt_hw_wdt_init(void)
 
     return RT_EOK;
 }
-INIT_BOARD_EXPORT(rt_hw_wdt_init);
+INIT_DEVICE_EXPORT(rt_hw_wdt_init);