LU-10094 mdc: dir page ldp_hash_end mistakenly adjusted

LU-10094 mdc: dir page ldp_hash_end mistakenly adjusted

On system PAGE_SIZE > 4k, mdc_adjust_dirpages() adjusts dir page
end hash with le64_to_cpu() value, but it should be little endian.

Fixes: 9d087dfd0fd ("LU-4516 mdc: missing lexxx_to_cpu in
mdc_read_entry")

This patch is back-ported from the following one:
Lustre-commit: d8b19ae6617733df003a906aca1791791a5f0eff
Lustre-change: https://review.whamcloud.com/35517

Test-Parameters: clientarch=ppc64 envdefinitions=ONLY="18 22 32 48" \
testlist=sanity

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I89bb8b93f1fe5f7962f0b80d122ef9965cf15c63
Reviewed-on: https://review.whamcloud.com/35812
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>