firmware: cs_dsp: Fix new control name check

firmware: cs_dsp: Fix new control name check

Before adding a new FW control, its name is checked against
existing controls list. But the string length in strncmp used
to compare controls names is taken from the list, so if beginnings
of the controls are matching,  then the new control is not created.
For example, if CAL_R control already exists, CAL_R_SELECTED
is not created.
The fix is to compare string lengths as well.

Fixes: 6477960755fb ("ASoC: wm_adsp: Move check for control existence")
Signed-off-by: Vlad Karpovich <vkarpovi@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230815172908.3454056-1-vkarpovi@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>