clk: ti: dm814x: Add of_node_put() to prevent memory leak

clk: ti: dm814x: Add of_node_put() to prevent memory leak

In function dm814x_adpll_early_init, variable np takes the value
returned by of_find_node_by_name, which gets a node but does not put it.
If np is not put before return, it may cause a memory leak. Hence put np
before return.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lkml.kernel.org/r/20190804163328.6693-1-nishkadg.linux@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>