pdbgproxy: Fix clang warning -Wformat
pdbgproxy: Fix clang warning -Wformat

... and use explicit endian conversion macros for clarity.

Signed-off-by: Amitay Isaacs <a505e7c038746dbeb3edcd8d146dbd515432801f@ozlabs.org>
Reviewed-by: Alistair Popple <e9adbcf81c8a36ccc628e09bc92d0e25e1c8e501@popple.id.au>

open-power/pdbg,open-power/pdbg,open-power/pdbg