env: Drop env_relocate_spec() in favour of env_load()

env: Drop env_relocate_spec() in favour of env_load()

This is a strange name for a function that loads the environment. There is
now only one implementation of this function, so use the new env_load()
function directly instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>