PCI: rzg3s-host: Initialize MSI status bitmap before use

PCI: rzg3s-host: Initialize MSI status bitmap before use

Initialize rzg3s_pcie_msi_irq() MSI status bitmap before use.

Fixes: 7ef502fb35b2 ("PCI: Add Renesas RZ/G3S host controller driver")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/all/202512070218.XVMUQCl7-lkp@intel.com
Closes: https://lore.kernel.org/all/202512061812.Xbqmd2Gn-lkp@intel.com
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251209125122.304129-1-claudiu.beznea.uj@bp.renesas.com