aec62xx: Fix kernel oops in driver's probe function

Add pci_enable_device() to aec62xx probe function
before doing any I/O.

Original probe function tries to read from device's
PCI region 4 before calling ide_setup_pci_device().
Since the device is not enabled at this point,
on machines that have no firmware PCI initialization
(e.g. ASUS WL-700gE router), corresponding PCI BAR 
is 0 and the following inb() causes a kernel oops.

Signed-off-by: Aleksandar Radovanovic <biblbroks@sezampro.yu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>