elf: Do not search HWCAP subdirectories in statically linked binaries

This functionality does not seem to be useful since static dlopen
is mostly used for iconv/character set conversion and NSS support.
gconv modules are loaded with full paths anyway, so that the
HWCAP subdirectory logic does not apply.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>