kirkwood_egiga: updates: fix DRAM mapping and typo

DRAM window mapping uses kirkwood-provided functions instead
of global gd as do other drivers--fix this.

Also, fix a typo in a comment

Signed-off-by: Albert Aribaud <albert.aribaud@free.fr>
Acked-by: Prafulla Wadaskar <prafulla@marvell.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>