msm: mhi_dev: free allocated memory in reverse order of allocation

Freeing cmd_ctx before ereqs will result into NULL ptr
dereference. Freeing memory in proper order.

Change-Id: Ie999017685574e940685eee3b7c205ebe1672664
Signed-off-by: Nitesh Gupta <nitegupt@codeaurora.org>
Signed-off-by: Gauri Joshi <gaurjosh@codeaurora.org>