PCI/switchtec: Correct bool variable type assignment

Use "true" instead of 1 to initialize "bool use_dma_mrpc".  This resolves
the following Coccinelle warning:

  drivers/pci/switch/switchtec.c:28:12-24: WARNING: Assignment of 0/1 to bool variable

Link: https://lore.kernel.org/r/20200521200439.1076672-1-kw@linux.com


Signed-off-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>