bus: bt1-axi: change to use devm_clk_get_enabled() helper

Use devm_clk_get_enabled() instead of devm_clk_get() to make the code
cleaner and avoid calling clk_disable_unprepare()

Signed-off-by: Wu Bo <bo.wu@vivo.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>