Reduce wishbone address size to 32-bit

Reduce wishbone address size to 32-bit

For now ... it reduces the routing pressure on the FPGA

This needs manual adjustment of the address decoder in soc.vhdl, at
least until I can figure out how to deal with std_match

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
# Conflicts:
#	soc.vhdl

# Conflicts:
#	soc.vhdl