net/dumbpipe: fix build on 32 bit platforms

The patch applied to this port works for powerpc64 but not for armv7.
Replace it with the patch from net/sendme, which works for both.

See also: e46a4cfed19eaedd0828758d075975dc37e28a41
See also: d4de8e372e2e8f829afe06d2ea4aa8528d2d96d2
MFH: 2026Q2
Approved by: portmgr (build fix blanket)

(cherry picked from commit 3baccc108e98bdede550599b3bbf74884b921c10)