dt-bindings: mfd: sl28cpld: Drop sa67mcu compatible

dt-bindings: mfd: sl28cpld: Drop sa67mcu compatible

I was just informed that this product is discontinued (without being
ever released to the market). Pull the plug and let's not waste any more
maintainers time and revert commit a598ae45f48d ("dt-bindings: mfd:
sl28cpld: Add sa67mcu compatible").

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Michael Walle <mwalle@kernel.org>
Link: https://patch.msgid.link/20260302122540.1377444-4-mwalle@kernel.org
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>