Generic-arm-none-eabi-gcc-cortex-m7: use SP float depending on NuttX config

Not all m7 boards support double, as for example the STM32F745.

platforms/nuttx/cmake/Platform/Generic-arm-none-eabi-gcc-cortex-m7.cmake

@@ -1,5 +1,12 @@
 
-set(cpu_flags "-mcpu=cortex-m7 -mthumb -mfpu=fpv5-d16 -mfloat-abi=hard")
+if (CONFIG_ARCH_DPFPU)
+	message(STATUS "Enabling double FP precision hardware instructions")
+	set(mfpu_type "fpv5-d16")
+else()
+	set(mfpu_type "fpv5-sp-d16")
+endif()
+
+set(cpu_flags "-mcpu=cortex-m7 -mthumb -mfpu=${mfpu_type} -mfloat-abi=hard")
 
 set(CMAKE_C_FLAGS "${cpu_flags}" CACHE STRING "" FORCE)
 set(CMAKE_CXX_FLAGS "${cpu_flags}" CACHE STRING "" FORCE)