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: Ic549f840db998385323e89b3f3dbe2e4349b932e
Signed-off-by: Jilai Wang <quic_jilaiw@quicinc.com>