PRSDK-8534: migration to sysbios 6.82

PRSDK-8534: migration to sysbios 6.82

 - Updated toolchains
    - Bios: bios_6_82_00_16
    - XDC : xdctools_3_61_00_16_core
    - TI CGT: ti-cgt-arm_20.2.0.LTS
    - GCC CGT: gcc-arm-9.2-2019.12-x86_64-arm-none-eabi
    - C66x TI CGT: ti-cgt-c6000_8.3.2
    - Eve CGT: arp32_1.0.8
 - Commented example build for platforms not supported in latest Bios
 - Updated A8 to use GCC toolchains for all platforms
 - Updated A8 and A15 Rules
    - Updated to use std libs from gnu\targets\arm\libs\install-native\arm-none-eabi\lib\thumb\v7-a\hard
    - Removed nano.specs from linker option as the nano libs are not supported under v7-a
    - Link the libgcc from compiler from lib/gcc/arm-none-eabi/9.2.1/thumb/v7-a+fp/hard

Signed-off-by: Prasad Konnur <prasadkonnur@ti.com>