elf: Catch up with defining EF_ARM_EABI_VERSION in elf_common.h

FreeBSD defines EF_ARM_EABI_VERSION in a non-standard way (at least
differently than everybody else). We use this only in elf*machdep.c to
make sure the image is new enough. Switch to the more standard way of
defining this and adjust other constants to match.

Fixes: c52c98e69a2e
Sponsored by: Netflix