ARM: brcmstb: Add debug UART entry for 74165

BCM74165 uses the same address map as the 7278 family (v7 memory map)
therefore re-use that constant and shift down the other labels to keep
numerical ordering.

Link: https://lore.kernel.org/r/20240129184651.2405485-1-florian.fainelli@broadcom.com


Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>