ANDROID: GKI: net: Add the get current NAPI context API

Commit 69235aa8 ("net: Remove the get current NAPI context API")
removed the definition of get_current_napi_context() as rmnet_data
was no longer using it. However, the rmnet_data change to use its
NAPI in multiple contexts was prone to race in hotplug scenarios.

Add back get_current_napi_context() and current_napi to the
softnet_data struct.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
(cherry picked from commit 05b3252c)
[surenb cherry-picked from
05b3252c net: Add the get current NAPI context API
to fix ABI diffs caused by get_current_napi_context function]

Bug: 151108843
Test: build
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I4d5b81c734e4a5daa2fae3cb7d6538821d46ff64
Merged-In: I4d5b81c734e4a5daa2fae3cb7d6538821d46ff64