pwm: meson: Fix g12a ao clk81 name

commit 9e4fa80a upstream.

Fix the name of the aoclk81 clock. Apparently name aoclk81 as used by
the vendor driver was changed when mainlining the g12a clock driver.

Fixes: f41efceb ("pwm: meson: Add clock source configuration for Meson G12A")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>