boards: nxp: mimxrt1170_evk: document flash support for EVKB

Flash support for RT1170 EVKB was fixed with cfb7322 (drivers: flash:
flash_mcux_flexspi: add support for W25Q512NW-IQ/IN). Document this
support in the board page.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>

Author: danieldegrasse

boards/nxp/mimxrt1170_evk/doc/index.rst

@@ -157,7 +157,7 @@ RT1170 EVKB (``mimxrt1170_evk@B//cm7/cm4``)
 +-----------+------------+-------------------------------------+-----------------+-----------------+
 | CAAM RNG  | on-chip    | entropy                             | Supported (M7)  | No support      |
 +-----------+------------+-------------------------------------+-----------------+-----------------+
-| FLEXSPI   | on-chip    | flash programming                   | Supported (M7)  | No support      |
+| FLEXSPI   | on-chip    | flash programming                   | Supported (M7)  | Supported (M7)  |
 +-----------+------------+-------------------------------------+-----------------+-----------------+
 | SDHC      | on-chip    | SD host controller                  | Supported (M7)  | Supported (M7)  |
 +-----------+------------+-------------------------------------+-----------------+-----------------+