Restore some memory exports to uefi::table::boot

The next release already has a fair number of breaking changes going into it, so
restore a few public exports to uefi::table::boot to reduce the number of
changes users have to make on upgrade. Specifically, `MemoryAttribute`,
`MemoryDescriptor`, and `MemoryType`.

This module will be deprecated eventually (replaced by `uefi::boot`), so these
re-exports will eventually go away in some future release.

Author: nicholasbishop

uefi/src/table/boot.rs

@@ -1,6 +1,8 @@
 //! UEFI services available during boot.
 
-pub use uefi_raw::table::boot::{EventType, InterfaceType, Tpl};
+pub use uefi_raw::table::boot::{
+    EventType, InterfaceType, MemoryAttribute, MemoryDescriptor, MemoryType, Tpl,
+};
 
 use super::Revision;
 use crate::data_types::PhysicalAddress;