[Qemu-trivial] migration: Fix 32 bit compiler errors

[Stefan Weil]

Obviously that code was never before compiled on 32 bit hosts.
The RDMA API uses lots of uint64_t values and the code casts them
to and from pointers.

I tried to fix the compilation but did not run any runtime tests.

I think the first two patches are trivial, but the third one might
not be trivial, so please review it carefully.

Regards
Stefan

[PATCH 1/3] migration: Fix coding style (whitespace issues)
[PATCH 2/3] migration: Fix some 32 bit compiler errors
[PATCH 3/3] migration: Fix remaining 32 bit compiler errors