rcu: Inline trivial wrapper function rcu_start_gp_per_cpu()

Given the changes that introduce note_gp_change(), rcu_start_gp_per_cpu()
is now a trivial wrapper function with only one caller.  This commit
therefore inlines it into its sole call site.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: ce3d9c03d1fa079678cc8df1517011e215517cda
Signed-off-by: Kishan Kumar <kishank@codeaurora.org>