x86: add PATA support to generic and 64 subtargets

PATA support has been removed from x86-generic without any note in LEDE
r538. Not including them makes the generated images incompatible with older
(and some newer) hardware without any significant gain.

Add it back, and also add the same drivers (as far as available) to x86-64.

Signed-off-by: Andreas Ziegler <github@andreas-ziegler.de>
[Matthias Schiffer: add back x86-generic, update commit message]
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>