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: I0630484fe5678335ed3246dc39e034b6a83d8d40
Signed-off-by: Jilai Wang <quic_jilaiw@quicinc.com>