flash: nor: use binary prefixes consistently

flash: nor: use binary prefixes consistently

When printing memory sizes standard ISO 80000-1 prefixes should be used.
Also a space should be added between any number and its unit according
to papers publication rules.

Change-Id: Id1d35e210766b55c201de4e80ac165d8d0414d0a
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/6416
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>