Previously, elfcopy defines:

VMA:  section virtual address
LMA:  PHDR(p_vaddr)

While binutils(libbfd) defines:

VMA:  section virtual address and PHDR(p_vaddr).
LMA:  PHDR(p_paddr)

For elfcopy, p_paddr is considered not meaningful and is always set
to the same value as p_vaddr.

elfcopy was implemented that way because I thought p_paddr is not
used/meaningful according to the ELF ABI. However it turned out
p_paddr is at least used in some ELF files, e.g. the FreeBSD kernel.

This change made elfcopy treat p_paddr as LMA, same as libbfd.

(However, some VMA/LMA related command line option still need tweaking
to make them compatible with binutils objcopy. This will be improved
later)

Ticket: #524