soc: nxp: imxrt: correct FCB offset for iMXRT1011 SOC to 0x400

Unlike the remainder of the RT10xx series, the RT1011 SOC requires that
the flash configuration block be placed at an offset of 0x400 bytes,
instead of the start of the flash.

Fixes #70090

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