bus: brcmstb_gisb: correct support for 64-bit address output
The GISB bus can support addresses beyond 32-bits. So this commit
corrects support for reading a captured 64-bit address into a 64-bit
variable by obtaining the high bits from the ARB_ERR_CAP_HI_ADDR
register (when present) and then outputting the full 64-bit value.