include/linux/compiler.h: reject gcc 3 < gcc 3.2

The kernel doesn't compile with GCC <3.2, do not allow it to succeed if GCC
3.0.x or 3.1.x are used.

Signed-off-by: Alistair John Strachan <s0348365@sms.ed.ac.uk>
Signed-off-by: Adrian Bunk <bunk@stusta.de>