boards/nucleo-f722ze: Add periph_can support

cpu/stm32: Add CAN support for f722ze board

f722ze board has ONLY 1 CAN interface, fix compiling error which
treats f722xx has more than 1 CAN.

boards/nucleo-f722ze/Kconfig

@@ -21,6 +21,7 @@ config BOARD_NUCLEO_F722ZE
     select HAS_PERIPH_TIMER
     select HAS_PERIPH_UART
     select HAS_PERIPH_USBDEV
+    select HAS_PERIPH_CAN
 
     # Put other features for this board (in alphabetical order)
     select HAS_RIOTBOOT

boards/nucleo-f722ze/Makefile.features

@@ -8,6 +8,7 @@ FEATURES_PROVIDED += periph_rtt
 FEATURES_PROVIDED += periph_timer
 FEATURES_PROVIDED += periph_uart
 FEATURES_PROVIDED += periph_usbdev
+FEATURES_PROVIDED += periph_can
 
 # Put other features for this board (in alphabetical order)
 FEATURES_PROVIDED += riotboot

cpu/stm32/include/can_params.h

@@ -43,11 +43,13 @@ static const can_conf_t candev_conf[] = {
         .rcc_mask = RCC_APB1ENR1_CAN1EN,
 #else
         .rcc_mask = RCC_APB1ENR_CAN1EN,
+#if CANDEV_STM32_CHAN_NUMOF > 1
         .can_master = CAN1,
         .master_rcc_mask = RCC_APB1ENR_CAN1EN,
         .first_filter = 0,
         .nb_filters = 14,
 #endif
+#endif
 #if  defined(CPU_FAM_STM32F1)
         .rx_pin = GPIO_PIN(PORT_A, 11),
         .tx_pin = GPIO_PIN(PORT_A, 12),

cpu/stm32/include/candev_stm32.h

@@ -42,7 +42,7 @@ extern "C" {
 #elif defined(CPU_FAM_STM32F1) || defined(CPU_FAM_STM32F2) || defined(CPU_FAM_STM32F4)
 #define CANDEV_STM32_CHAN_NUMOF 2
 #elif defined(CPU_FAM_STM32F0) || defined(CPU_FAM_STM32F3) || \
-      defined(CPU_FAM_STM32L4) || DOXYGEN
+      defined(CPU_FAM_STM32L4) || defined(CPU_LINE_STM32F722xx) || DOXYGEN
 /** Number of channels in the device (up to 3) */
 #define CANDEV_STM32_CHAN_NUMOF 1
 #else
@@ -137,7 +137,6 @@ typedef struct {
 /** The number of receive FIFO */
 #define CAN_STM32_RX_MAILBOXES 2
 
-
 #ifndef CAN_STM32_RX_MAIL_FIFO
 /** This is the maximum number of frame the driver can receive simultaneously */
 #define CAN_STM32_RX_MAIL_FIFO 12