There is only one bank of NOR flash memory on ICU862 boards.
Remove code that attempts to deal with a second bank.

This also fixes build warnings:
flash.c: In function 'flash_init':
flash.c:120:12: warning: array subscript is above array bounds
[-Warray-bounds]
flash.c:121:12: warning: array subscript is above array bounds
[-Warray-bounds]
flash.c:124:12: warning: array subscript is above array bounds
[-Warray-bounds]

Signed-off-by: Wolfgang Denk <wd@denx.de>