clk/ti/adpll: allocate room for terminating null

The buffer allocated in ti_adpll_clk_get_name doesn't account for the
terminating null. This patch switches to devm_kasprintf to avoid
overflowing.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lkml.kernel.org/r/20191019140634.15596-1-steve@sk2.org


Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>