Kinetis enet: support multiple transmits between interrupts.  Accounts for the unlikely event that more than one packet has been transmitted before the tx done is processed

Kinetis enet: use rounded up MTU size for buffers. The buffers must be evenly divisible by 16, so round up the MTU size and use that for the buffer sizes

STM32 TIM: Fix comment

STM32 QEncoder: Fix typo

STM32 TIM: Fix typos and add forgotten bit

STM32 QEncoder: Fix some typos

Master

debug macros for AVR (take #2): Introduce debug macro hooks for AVR

When AVR_HAS_MEMX_PTR is enabled provide dbg macro hooks that place
the format strings in program memory releasing RAM for other tasks.

All AVR toolchain configuration names must end with _TOOLCHAIN to work properly with nuttx/tools/testbuilds.sh

SAMV7: Add logic to check if multiple banks are busy in TXINI interrupt processing.  This logic is probably necessary, but currently commented out because it is untested