msm: ipa3: add support for MHI burst mode

MHI channel burst mode is used to reduce link activity by reducing the
frequency of host initiated doorbells and device initiated link accesses.
This change adds support for mhi burst mode in IPA MHI driver, according to
MHI v0.45 spec.

CRs-Fixed: 990856
Change-Id: Iae170042b70c6eaf5bc05ea2b4a1ccdb7dd6f946
Acked-by: Nadine Toledano <nadinet@codeaurora.org>
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>