misc: pci_endpoint_test: Handle 64-bit BARs properly

misc: pci_endpoint_test: Handle 64-bit BARs properly

A 64-bit BAR consists of a BAR pair, where the second BAR has the
upper bits, so we cannot simply call pci_ioremap_bar() on every single
BAR index.

The second BAR in a BAR pair will not have the IORESOURCE_MEM resource
flag set. Only call ioremap on BARs that have the IORESOURCE_MEM
resource flag set.

pci 0000:01:00.0: BAR 4: assigned [mem 0xc0300000-0xc031ffff 64bit]
pci 0000:01:00.0: BAR 2: assigned [mem 0xc0320000-0xc03203ff 64bit]
pci 0000:01:00.0: BAR 0: assigned [mem 0xc0320400-0xc03204ff 64bit]
pci-endpoint-test 0000:01:00.0: can't ioremap BAR 1: [??? 0x00000000 flags 0x0]
pci-endpoint-test 0000:01:00.0: failed to read BAR1
pci-endpoint-test 0000:01:00.0: can't ioremap BAR 3: [??? 0x00000000 flags 0x0]
pci-endpoint-test 0000:01:00.0: failed to read BAR3
pci-endpoint-test 0000:01:00.0: can't ioremap BAR 5: [??? 0x00000000 flags 0x0]
pci-endpoint-test 0000:01:00.0: failed to read BAR5

Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>