wireguard: Do not mask error when disabling rp_filter
wireguard: Do not mask error when disabling rp_filter

It should be propagated to the caller, as we exit the function when
rp_filter cannot be disabled.

Signed-off-by: Sebastian Wicki <db043b2055cb3a47b2eb0b5aebf4e114a8c24a5a@isovalent.com>

tklauser/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium