ARM: 6954/1: zImage: fix Thumb2 breakage

Commit af3e4fd37a "ARM: 6859/1: Add writethrough dcache support for
ARM926EJS processor" broke Thumb2 compilation by omitting to maintain
the wide encoding for the added branch instructions which made the
ARM926EJ-S record smaller than expected, breaking the record walk code.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>