package/libqmi: fix build when libc doesn't define ARPHRD_RAWIP

package/libqmi: fix build when libc doesn't define ARPHRD_RAWIP

The ARPHRD_RAWIP symbol is used in the rmnet backend in the link
management support now included in libqmi.

If libc doesn't provide this symbol yet, define it ourselves. The
symbol will only be used if rmnet is enabled in the kernel anyway.

This patch will be included in the next libqmi 1.28.4.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
[yann.morin.1998@free.fr:
  - do an actual backport now it's been applied upstream
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>