msm: ipa: Fix the handling of default IPA header

Default IPA header is added or deleted from the driver
directly and not by user space application. This change
prevents adding/deleting it from user application which
may cause inconsistencies in the driver. Also the change
fixes the header reset function to skip on the correct
default header.

Change-Id: Ic813433655411f1447db8b0c15efdf64038d8c26
CRs-fixed: 2151146
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>