The variable which holds the parent names for the VPU clocks has a typo
in it. Fix this typo to make the variable naming in the driver
consistent. No functional changes.

Fixes: 41785ce5 ("clk: meson: meson8b: add the VPU clock trees")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>