ASoC: twl6040: fix spelling mistake

Fix spelling mistake in "High-Performance" option of twl6040 power mode.

Signed-off-by: Simon Wilson <simonwilson@google.com>
Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>