[nrf temphack] kconfig: Disallow FPU for SPM

Add depends on !IS_SPM in config FPU.
depends on !FPU gives a Kconfig dependency loop.

Signed-off-by: Øyvind Rønningstad <[email protected]>
(cherry picked from commit d0a048c)

Author: oyvindronningstad

arch/Kconfig

@@ -830,6 +830,7 @@ menu "Floating Point Options"
 config FPU
 	bool "Enable floating point unit (FPU)"
 	depends on CPU_HAS_FPU
+	depends on !IS_SPM
 	help
 	  This option enables the hardware Floating Point Unit (FPU), in order to
 	  support using the floating point registers and instructions.