accel/qaic: Drop redundant vfree() null check in sahara

The documentation for vfree() says that passing in NULL is ok. Therefore
we can drop the null check as redundant.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410301732.abF5Md4e-lkp@intel.com/


Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Youssef Samir <quic_yabdulra@quicinc.com>
Reviewed-by: Carl Vanderlip <quic_carlv@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241117202629.1681358-1-quic_jhugo@quicinc.com