liveupdate: reject LIVEUPDATE_IOCTL_CREATE_SESSION with invalid name length

liveupdate: reject LIVEUPDATE_IOCTL_CREATE_SESSION with invalid name length

A session name must not be an empty string, and must not exceed the
maximum size define in the uapi header, including null termination.

Fixes: 0153094d03df ("liveupdate: luo_session: add sessions support")
Cc: stable@vger.kernel.org
Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://lore.kernel.org/r/20260429212221.814107-2-luca.boccassi@gmail.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>