pcid/base bump + redox-driver-pci: 64-byte header reads

- base bump (b0e76065): pcid PCI 3.0 fallback no longer panics on
  extended config reads (returns 0xFFFFFFFF, drops writes).
- redox-driver-pci PciBus reads only the 64-byte standard header it
  consumes (vendor/device/class/subsystem), instead of the whole 4 KiB
  config file per device per poll cycle — safe on MCFG-less machines
  and cheaper everywhere.

local/recipes/drivers/redox-driver-pci/source/src/bus.rs

@@ -50,8 +50,20 @@ impl Bus for PciBus {
             }
 
             let config_path = path.join("config");
-            let config_data = match fs::read(&config_path) {
-                Ok(d) => d,
+            // Read only the 64-byte standard header: everything PciBus
+            // consumes (vendor/device at 0x00, class block at 0x08-0x0B,
+            // subsystem IDs at 0x2C-0x2F) lives there, and larger reads
+            // cross into PCIe extended space which does not exist on
+            // MCFG-less (PCI 3.0 I/O-port fallback) machines.
+            let config_data = match std::fs::File::open(&config_path) {
+                Ok(file) => {
+                    use std::io::Read;
+                    let mut buf = Vec::new();
+                    match file.take(64).read_to_end(&mut buf) {
+                        Ok(_) => buf,
+                        Err(_) => continue,
+                    }
+                }
                 Err(_) => continue,
             };