ata: libata-sff: make ata_resources_present() return 'bool'

ata_resources_present() returns 1 if the primary/secondary channel's PCI
resources are present,  0 if not -- the 'bool' type fits somewhat better
here than 'int'...

Use the *= operator, while at it...

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>