msm: ipa: Fix IPA driver compilation issues on sdxprairie

1. Add missing inline to static empty function.
   Issue hasn't been seen so far as msmnile uses different
   relevant defconfig configuration (CONFIG_IPA3_MHI_PROXY).
2. 64bit integer divide on 32bit CPU.
   Issue hasn't been seen so far as msmnile is 64bit CPU.

CRs-Fixed: 2260620
Change-Id: I119a1f81182ca53cb0b52fa74a60b63a788da7d9
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>