Callers must pass ELF machine, byte swapping and symbol LSB clearing
information to ELF loader. A.out loader needs page size information, pass
that too as a parameter.

Extract prototypes to a separate file. Move loader.[ch] and elf_ops.h under hw.

Adjust callers. Also use target_phys_addr_t instead of target_ulong for
addresses: loader addresses aren't virtual.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>