jasper: Disable debugging when building for xtensa

xtensa gcc is not able to generate correct code when compiling with -O0
enabled by --enable-debug. Instead of disabling package build it with
--disable-debug.

Fixes:
  http://autobuild.buildroot.net/results/5d17055027055ffd33fcd28b208130afb26343c9/



Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>