msm: npu: Avoid buffer overflow when handling get_property packet

If packet size is set to invalid value by firmware, when driver
tries to copy property content to memory, it could cause buffer
overflow. To avoid this, packet size needs to be checked to make
sure it's valid.

Change-Id: Iba048429f12aa7c003e5256bd026449c0b25e9d9
Signed-off-by: Jilai Wang <quic_jilaiw@quicinc.com>