On x86-64 there are several memory allocations before bootmem. To avoid
them stomping on each other they used to be all hard coded in bad_area().
Replace this with an array that is filled as needed.

This cleans up the code considerably and allows to expand its use.

Cc: peterz@infradead.org
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>