hv_sock: Return -EIO for malformed/short packets

hv_sock: Return -EIO for malformed/short packets

Commit f63152958994 fixes a regression, however it fails to report an
error for malformed/short packets -- normally we should never see such
packets, but let's report an error for them just in case.

Fixes: f63152958994 ("hv_sock: Report EOF instead of -EIO for FIN")
Cc: stable@vger.kernel.org
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20260423064811.1371749-1-decui@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>