configs: k2hk_evm: config: add common EVM configuration header

This patch adds a common config header file for all the Keystone II
EVM platforms. It combines a lot of general definitions in one file.
The common header included in the EVM should be specific configuration
header.

Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Hao Zhang <hzhang@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>