This fixes MSI operation on legacy PCI cards, which cannot issue 64bit MSIs.
The R-Car controller only has one MSI trigger address instead of two, one
for 64bit and one for 32bit MSI, set the address to 32bit PCIe space so that
legacy PCI cards can also trigger MSIs.

Link: https://lore.kernel.org/r/20201016120431.7062-1-marek.vasut@gmail.com
Fixes: 290c1fb3 ("PCI: rcar: Add MSI support for PCIe")
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: linux-renesas-soc@vger.kernel.org