ANDROID: vendor_hooks: Reduce pointless modversions CRC churn

When vendor hooks are added to a file that previously didn't have any
vendor hooks, we end up indirectly including linux/tracepoint.h.  This
causes some data types that used to be opaque (forward declared) to the
code to become visible to the code.

Modversions correctly catches this change in visibility, but we don't
really care about the data types made visible when linux/tracepoint.h is
included. So, hide this from modversions in the central vendor_hooks.h
file instead of having to fix this on a case by case basis.

Since this is a KMI frozen branch, existing vendor hook headers are left
as is to avoid KMI breakage due to CRC churn.

To avoid future pointless CRC churn, new vendor hook header files that
include vendor_hooks.h should not include linux/tracepoint.h directly.

Bug: 227513263
Bug: 226140073
Signed-off-by: Saravana Kannan <saravanak@google.com>
Change-Id: Ia88e6af11dd94fe475c464eb30a6e5e1e24c938b