support RNG on STM32L4.  add support for SAI1PLL and SAI2PLL.  fix some errors in defines and configs.

support RNG on STM32L4.  add support for SAI1PLL and SAI2PLL.  fix some errors in defines and configs.

STM32 DAC: Fix DMA support for STM32F2xxx and STM32F4xxx

STM32L4: Fix incorrect and conflicting definitions for STM32L4_NGPIOS and STM32L4_NGPIO_PORTS.  Now there is only STM32L4_NPORTS.

SAMV7 USB:  Fix a DMA related issue.  When DMA completes with NBUSYBK greater than zero, need to way for NBUSYBK interrupt.

i.MX6: Hmm.. I think the i.MX6 Solo Lite has global and private timers.  Note cleare from the reference manual

i.MX6: Revamp GIC initialization logic; add missing register bit definitions and initialization of GIC control register for secure cases

Rename CONFIG_SAMA5_HAVE_TRUSTZONE to CONFIG_ARCH_HAVE_TRUSTZONE; Eliminate CONFIG_SAMA5_SECURE; Add CONFIG_ARCH_TRUSTZONE_SECURE