package/oracle-mysql: use BR2_ENABLE_RUNTIME_DEBUG iso BR2_ENABLE_DEBUG

package/oracle-mysql: use BR2_ENABLE_RUNTIME_DEBUG iso BR2_ENABLE_DEBUG

BR2_ENABLE_DEBUG should just steer the availability of debug symbols and
should have no negative effect on performance.

Introduction of 'assert' statements, 'debug'-type builds with additional
logging, etc. should be steered by BR2_ENABLE_RUNTIME_DEBUG instead.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>