[PATCH] drivers/telephony/ixj: fix an array overrun

The Coverity checker noted that in
drivers/telephony/ixj.c:ixj_build_filter_cadence(), filter_en[4] or
filter_en[5] could be written to.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>