config: switch cc with libc in the config order

Some of the compiler options depend on the C library choice, (e.g.
whether core passes are needed).

Since the compiler menu comes before the C library menu, those options
may or may not be visible until the C library is chosen, leading to
either options being visible by the user (thus be puzzling as they would
not apply to his case), or invisible to him (yet again puzzling him).

Invert the order of the compiler and the C library in the menuconfig. It
anyway looks more rational, in the end.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # Bare metal config options

 ## select BARE_METAL

 ##

 ## help 'Bare metal' refers to those programs that run without any kernel.

 ## help

 ## help You probably want to say 'y' here if you plan to use your compiler

 ## help to build bootloaders. It is not yet suitable to build Linux kernels,

 ## help though, because the APCI stuff relies on the target C library headers

 ## help being available?!?!...