arch: disable cpu extensions

we don't use that in kernel mode to speed up
context switching, and noone needs floats and
such in the kernel anyway.

arch/x86/config/toolchain.cmake

@@ -16,7 +16,7 @@ set(CMAKE_RANLIB        ${TOOLCHAIN_PATH}/${CMAKE_EXECUTABLE_PREFIX}ranlib${CMAK
 set(CMAKE_SZE           ${TOOLCHAIN_PATH}/${CMAKE_EXECUTABLE_PREFIX}szr${CMAKE_EXECUTABLE_SUFFIX} CACHE INTERNAL "")
 set(CMAKE_STRIP         ${TOOLCHAIN_PATH}/${CMAKE_EXECUTABLE_PREFIX}strip${CMAKE_EXECUTABLE_SUFFIX} CACHE INTERNAL "")
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -target i686-none -m32")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -target i686-none -m32 -mgeneral-regs-only")
 set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -target i686-none -m32")
 
 configure_file(