{delta,zylonite}/lowlevel_init.S: fix typo

Commit 9d803d8c mistakenly changed some constants
from 0x300 into 300 - this patch fixes it.

Pointed out by Tom Evans <tom@ceos.com.au>, see
http://article.gmane.org/gmane.comp.boot-loaders.u-boot/51992

 for
details.

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