Based on commit c17af71d2c (package/audit: not available for musl) add a
comment that explains why audit is disabled for musl.
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>