PCI: versatile: Enable COMPILE_TEST

Since commit a574795b

 ("PCI: generic,versatile: Remove unused
pci_sys_data structures") the build dependency on ARM is gone, so let's
enable COMPILE_TEST for versatile.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>