package/tremor: select libogg package

tremor depends on libogg package but doesn't select it
in Config.in. so libogg build is trigged at Makefile level.

Since 28f67899, the build
stop if a package build is trigged at Makefile level without
being selected at Config.in level.

Fixes:
http://autobuild.buildroot.net/results/0da/0da3265f0f1e499f5d34ed32b0d13a2eda53f976



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>