Kernel/PCI: Add helper to determine if device can access IO space

Author: https://github.com/supercomputer7
Commit: 0669dd82e2
Pull-request: https://github.com/SerenityOS/serenity/pull/6277
Reviewed-by: https://github.com/ElectrodeYT
Reviewed-by: https://github.com/awesomekling

Kernel/PCI/Access.cpp

@@ -204,6 +204,10 @@ void disable_memory_space(Address address)
 {
     write16(address, PCI_COMMAND, read16(address, PCI_COMMAND) & ~(1 << 1));
 }
+bool is_io_space_enabled(Address address)
+{
+    return (read16(address, PCI_COMMAND) & 1) != 0;
+}
 
 void enable_interrupt_line(Address address)
 {