net/sendme: fix build on non-x86

The netdev crate has the value of ioctl SIOCGIFXMEDIA hardcoded for x86.
Add definitions for other architectures to fix the build.

See also: https://github.com/shellrow/netdev/issues/170
Approved by: portmgr (build fix blanket)
MFH: 2026Q2

(cherry picked from commit d4de8e372e2e8f829afe06d2ea4aa8528d2d96d2)