[ARM] 4517/1: S3C: Fix debug macros for ARM926 output

Check for ARM926 based S3C24XX based devices as these
only have 64 byte FIFOs, and do not have the model
detection refisters in the same place as the ARM920
based CPUs

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>