eal: remove size for setting runtime directory

eal: remove size for setting runtime directory

The size argument to eal_set_runtime_dir is useless and was
being used incorrectly in strlcpy. It worked only because
all callers passed PATH_MAX which is same as sizeof the destination
runtime_dir.

Note: this is an internal API so no user exposed change.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>