Debugging facility improvements.

Debugging facility improvements.

 - Hook up malloc() debug code via CONFIG_DEBUG_MALLOC. Only show it in
   menuconfig if at least DEBUG or SPEW are selected as loglevel, as this
   code does additional printk(BIOS_DEBUG, ...) calls which would otherwise
   not be visible anyway.

 - Similarly, make DEBUG_CAR and REALMODE_DEBUG only visible if thr DEBUG or
   SPEW loglevel is selected.

 - Get rid of a custom "debug" macro, use printk() as usual.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Peter Stuge <peter@stuge.se>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6054 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1