PCI: brcmstb: Rename .map_bus() functions to end with 'map_bus'

Rename the .map_bus() functions to end with 'map_bus' so they're easy to
find with, e.g., 'git grep "^static.*_map_bus" drivers/pci/'.

[bhelgaas: rename brcm_pcie_map_bus32() to brcm7425_pcie_map_bus() for
better cscope-ability (".*_map_bus" is not the same as ".*_map_bus.*")]
Link: https://lore.kernel.org/r/20220725151258.42574-8-jim2101024@gmail.com


Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>