No functional change. Move the register defines and other macros from
pcie-designware.c to pcie-designware.h. This is in preparation to split the
pcie-designware.c file into designware core file and host-specific file.

While at that also fix a checkpatch warning.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-By: NJoao Pinto <jpinto@synopsys.com>