regmap: irq: Free the regmap-irq mutex

We do not currently free the mutex allocated by regmap-irq, do so.

Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://patch.msgid.link/20250731-regmap-irq-nesting-v1-1-98b4d1bf20f0@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>