msm: ipa: add support to query and use smem restricted bytes

Currently WAN driver client is hard-coding this value which is
HW version dependent causing AP and modem to go out of sync.

Change-Id: I09a988a0c35ade72a96617281f963bdb0feb6dec
Acked-by: Sunil Kumar Paidimarri <hisunil@qti.qualcomm.com>
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>