SAMV7 MCAN: When bitrate is changed, the MCAN has to be reset and there are lots of issues related to getting back to a healthy state if there is multithreaded access to the MCAN device.  This commit handles a few of those issues, but there are more

Added definitions for STM32F303K6, STM32F303K8, STM32F303C6, STM32F303C8, STM32F303RD, and STM32F303RE devices.

STM32F303C8, STM32F303RD, and STM32F303RE devices.

SAMV7 USB device: Fix base address of USBHS RAM; remove a bad assertion; fix clearing of endpoint interrupts

SAMV71 MCAN: Change Kconfig so that zero is no longer the default value for the size of RXFIFO0, RXFIFO1, and TXFIFIQ.  In fact, zero is not an illegal value

SAMV7 SPI slave:  Loop in the interrupt handler; RDRF and TXNE events should occur very closely in time

Add Shared IRQ support for UART w/multi port.

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>

Rename sam_spi_slave_initialize to up_spi_slave_initialize for better symmety with the Master SPI interface definition

SAMV7 MCAN: Fix DCACHE configuration dependency; Mkae sure DMA buffers are aligned to the cache line size at the end, Make RX FIFO1 the high priority FIFO and it it preference for RX input