ext/hal/nxp/imx: Import the nxp imx6 freertos bsp

This code component is used to add Zephyr support on iMX6SX
processors, exclusively on Cortex M4 core, and to speed up the
development process it was decided to have it based on NXP FreeRTOS BSP
implementation.

The i.MX FreeRTOS BSP is split into separate downloadable packages,
based on SoC. The packages share most of the peripheral driver files
and here they are combined together.

The source code was imported from the following folders:
FreeRTOS_BSP_1.0.1_iMX6SX/platform/drivers
FreeRTOS_BSP_1.0.1_iMX6SX/platform/devices

This source code depends on headers and sources from zephyr:
    ext/hal/cmsis

Origin: i.MX 6SoloX FreeRTOS BSP 1.0.1 for Cortex-M4 Peripheral Driver
License: BSD 3-Clause
URL: https://www.nxp.com/webapp/Download?colCode=FreeRTOS_MX6SX_1.0.1_LINUX&appType=license


commit: no commit hash
Purpose: The peripheral driver wraps the H/W for i.MX6SX M4 core
Maintained-by: External

Signed-off-by: Stanislav Poboril <stanislav.poboril@nxp.com>