msm: ipa3: Pointer Check and Fix overflow in Header Deletion

During header deletion, if there is a HPC referencing to a header,
and the header is deleted, the later commit will cause
writing garbage values to the HW during commit.

Change-Id: Ib8bb490e38c57d975c21e5848850cd79263c95fe
Signed-off-by: Jagadeesh Ponduru <jponduru@codeaurora.org>