staging: mt7621-pci: remove 'offset' with mem and io resource sizes

staging: mt7621-pci: remove 'offset' with mem and io resource sizes

Offset contains resources size for both io and memory resources.
Those fields are directly initialized to zero and set up using
'pci_add_resource_offset' function. Instead of doing that remove
them and use directly function 'pci_add_resource' where zero is
passed directly to its internal call to 'pci_add_resource_offset'.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20201123093637.8300-3-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>