pci: designware: Update MSI mapping unconditionally

Expression to calculate update_msi_mapping in code handling writes to
DESIGNWARE_PCIE_MSI_INTR0_ENABLE is missing an ! operator and should
be:

    !!root->msi.intr[0].enable ^ !!val;

so that MSI mapping is updated when enabled transitions from either
"none" -> "any" or "any" -> "none". Since that register shouldn't be
written to very often, change the code to update MSI mapping
unconditionally instead of trying to fix the update_msi_mapping logic.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: qemu-devel@nongnu.org
Cc: qemu-arm@nongnu.org
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/pci-host/designware.c

@@ -297,16 +297,10 @@ static void designware_pcie_root_config_write(PCIDevice *d, uint32_t address,
         root->msi.base |= (uint64_t)val << 32;
         break;
 
-    case DESIGNWARE_PCIE_MSI_INTR0_ENABLE: {
-        const bool update_msi_mapping = !root->msi.intr[0].enable ^ !!val;
-
+    case DESIGNWARE_PCIE_MSI_INTR0_ENABLE:
         root->msi.intr[0].enable = val;
-
-        if (update_msi_mapping) {
-            designware_pcie_root_update_msi_mapping(root);
-        }
+        designware_pcie_root_update_msi_mapping(root);
         break;
-    }
 
     case DESIGNWARE_PCIE_MSI_INTR0_MASK:
         root->msi.intr[0].mask = val;