cfi intel: fixing faulty flash write error message

Writing to Intel CFI flash with unaligned tail bytes raised a false
error message although all data was programmed successfully. e.g.:
> flash write_image image 0x602e0000 bin
> Programming at 0x602e0000, count 0x00000002 bytes remaining
> couldn't write word at base 0x60000000, address 0x602e0000
> error writing to flash at address 0x60000000 at offset 0x002e0000
Root cause for this false error was a mixup of two result variables
introduced with ecc8041c.

Change-Id: Ib6b85293dbed946a36a307e5b198c47b901145bf
Signed-off-by: Alexander Kurz <akurz@blala.de>
Reviewed-on: http://openocd.zylin.com/3233
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>