nxp: add flexspi driver support

Flexspi driver now introduces read/write/erase APIs for complete flash
size, FAST-READ are by default used and IP bus is used for erase, read
and write using flexspi APIs.

Framework layer is currently embedded in driver itself using flash_info
defines.

Test cases are also added to confirm flash functionality currently under
DEBUG flag.

Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Change-Id: I755c0f763f6297a35cad6885f84640de50f51bb0
9 files changed