fmu-v5x: enable DShot

Only the first 6 FMU pins support it.
DMA conflict with UART8, which is the GPS2 port.

boards/px4/fmu-v5x/default.cmake

@@ -24,7 +24,7 @@ px4_add_board(
 		camera_trigger
 		differential_pressure # all available differential pressure drivers
 		distance_sensor # all available distance sensor drivers
-		#dshot
+		dshot
 		gps
 		#heater
 		#imu # all available imu drivers

boards/px4/fmu-v5x/nuttx-config/nsh/defconfig

@@ -258,7 +258,6 @@ CONFIG_UART7_RXDMA=y
 CONFIG_UART7_TXBUFSIZE=3000
 CONFIG_UART8_BAUD=57600
 CONFIG_UART8_RXBUFSIZE=600
-CONFIG_UART8_RXDMA=y
 CONFIG_UART8_TXBUFSIZE=1500
 CONFIG_USART1_BAUD=57600
 CONFIG_USART1_RXBUFSIZE=600

boards/px4/fmu-v5x/src/board_config.h

@@ -426,6 +426,8 @@
 
 #define DIRECT_INPUT_TIMER_CHANNELS  8
 
+#define BOARD_DSHOT_MOTOR_ASSIGNMENT {3, 2, 1, 0, 4, 5, 6, 7};
+
 
 /* User GPIOs
  *

boards/px4/fmu-v5x/src/timer_config.c

@@ -83,7 +83,12 @@ __EXPORT const io_timers_t io_timers[MAX_IO_TIMERS] = {
 		.last_channel_index = 3,
 		.handler = io_timer_handler0,
 		.vectorno =  STM32_IRQ_TIM1CC,
-
+		.dshot = {
+			.dma_base = STM32_DMA2_BASE,
+			.dmamap = DMAMAP_TIM1_UP,
+			.start_ccr_register = TIM_DMABASE_CCR1,
+			.channels_number = 4u /* CCR1, CCR2, CCR3 and CCR4 */
+		}
 	},
 	{
 		.base = STM32_TIM4_BASE,
@@ -94,6 +99,12 @@ __EXPORT const io_timers_t io_timers[MAX_IO_TIMERS] = {
 		.last_channel_index = 5,
 		.handler = io_timer_handler1,
 		.vectorno =  STM32_IRQ_TIM4,
+		.dshot = {
+			.dma_base = STM32_DMA1_BASE,
+			.dmamap = DMAMAP_TIM4_UP,
+			.start_ccr_register = TIM_DMABASE_CCR2,
+			.channels_number = 2u /* CCR2 and CCR3 */
+		}
 	},
 	{
 		.base = STM32_TIM12_BASE,