IB/uverbs: Make ib_uverbs_release_event_file() static

ib_uverbs_release_event_file() is only used in uverbs_main.c, so make it
static to that file.  Also move the definition before the first use, so
a forward declaration is not needed.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --cc drivers/infiniband/core/uverbs.h
Simple merge

diff --cc drivers/infiniband/core/uverbs_main.c
Simple merge