[En-Nut-Discussion] [r5282] Added context_fpu.c for cm3

[Michael Fischer]

Hello List,

I have added a context_fpu.c but not fully tested. Please
can someone check it too? I am not sure if fpscr, the
Floating Point Status register must be saved too in case
of a context switch.

The context switch is still working, this was tested with
CrossWorks for ARM. But I have not test it with floating
point calculation in different threads.

The file was checked in that someone can take a look too.

Best regards,
Michael