clk: bcm2835: add missing release if devm_clk_hw_register fails

In the implementation of bcm2835_register_pll(), the allocated pll is
leaked if devm_clk_hw_register() fails to register hw. Release pll if
devm_clk_hw_register() fails.

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Link: https://lore.kernel.org/r/20200809231202.15811-1-navid.emamdoost@gmail.com
Fixes: 41691b88

 ("clk: bcm2835: Add support for programming the audio domain clocks")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>