Recently Broadcom added support for NVRAMs with entries for multiple
PCIe devices. One of the supported formats is based on prefixes defined
like: devpath0=pcie/1/4/ and entries like 0:foo=bar 0:baz=qux etc.

Unfortunately there are also a bit older devices using different way of
defining prefixes, e.g. SmartRG SR400ac (2 x BCM43602) with entries:
devpath0=pci/1/1/
devpath1=pci/2/1
Broadcom stated this old format will never be used/supported by brcmfmac
but given the simplicity of this patch I'll insist on supporting it.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>