x86/boot/compressed: Move 32-bit entrypoint code into .text section

Move the code that stores the arguments passed to the EFI entrypoint
into the .text section, so that it can be moved into a separate
compilation unit in a subsequent patch.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-3-ardb@kernel.org