common: board_f: vid: Add VID specific API to adjust core voltage

Adds a VID specific API in init_sequence_f and spl code flow
namely init_func_vid which is required to adjust core voltage.

VID specific code is required in spl, hence moving flag CONFIG_VID
out of spl flags.

Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>