trivial: style changed file

trivial: Fix compiler warnings

- Declare unused variables
- Move variable initialization to prevent uninitialized use
- Correctly store bitwise operation result
- Fixup memset calls to use correct size
- Add missing return statement to functions
- Conditionally define functions that are used conditionally

libsel4allocman: use correct word size

Fix all the whitespace

- remove trailing whitespace
- remove duplicate blank lines
- remove blank lines at end of files

Fix licenses

libsel4allocman: Memory mapped device IO allocation support

Adds support at the top level allocman interface for allocating
objects at a particular physical address (allocman_utspace_alloc_at)
as well as fullfilling allocations from 'device memory'. Uses this
for implementing the additional vka interface function vka_utspace_alloc_at

The split and twinkle untyped allocators are updated to support this
new interface. split implements the 'alloc_at' by brute force searches
over its untypeds, whilst twinkle with its lack of book keeping
is forced to fail any 'alloc_at' request

libsel4allocman: Fix missing initialised field.

This commit fixes an instance where a struct was initialised with an incorrect
number of fields. The compiler figured out what was meant, so no harm was done,
but the previous code was technically incorrect.

libsel4allocman: Make allocman 64-bit friendly

When compiling for 32-bit there may be spurious warnings due to
some interface type changes. These will eventually be fixed when
other libraries are made 64-bit compatible