kconfig: openthread: remove FPU dependency for prebuilt libraries

remove `depends on FPU` for `OPENTHREAD_LIBRARY_AVAILABLE` as
it is not used by default now

Signed-off-by: Maciej Baczmanski <maciej.baczmanski@nordicsemi.no>

Author: maciejbaczmanski

subsys/net/openthread/Kconfig.defconfig

@@ -25,7 +25,6 @@ config OPENTHREAD_LIBRARY_AVAILABLE
 		    OPENTHREAD_NORDIC_LIBRARY_FTD || OPENTHREAD_NORDIC_LIBRARY_MTD
 	depends on !OPENTHREAD_COPROCESSOR
 	depends on SOC_NRF52840 || SOC_NRF5340_CPUAPP
-	depends on FPU
 
 choice OPENTHREAD_IMPLEMENTATION
 	default OPENTHREAD_LIBRARY if OPENTHREAD_LIBRARY_AVAILABLE