msm: ipa: add IPA driver initialization checks to public IPA APIs

When IPA HW is not enabled/used, IPA driver is not loaded.
In these cases, there's a need to make sure that the public
IPA API calls will fail accordingly.
The change was made in all API calls which are used outside
of IPA driver and IPA WAN driver context.

Change-Id: If46c65ef428ee114c4850ca2f459846a3280fe3c
Acked-by: David Arinzon <darinzon@qti.qualcomm.com>
Signed-off-by: Sivan Reinstein <sivanr@codeaurora.org>