PCI: mobiveil: Add Kconfig/Makefile entries

commit 9af6bcb1 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP
driver") did not add the configuration and build infrastructure to
configure and build the mobiveil controller driver, so at present the
driver code is in the kernel but cannot be compiled.

Add the mobiveil controller driver Kconfig/Makefile infrastructure.

Fixes: 9af6bcb1 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP
driver")
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>