elf: Simplify output of hwcap subdirectories in ld.so help

The print_hwcap_1 machinery was useful for the legacy hwcaps
subdirectories, but it is not worth the trouble now that they
are gone.

Signed-off-by: Javier Pello <devel@otheo.eu>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>