Loongson64 load kernel at 0x82000000 and allocate exception vectors
by ebase. So we don't need to reserve space for exception vectors
at head of kernel.
Signed-off-by: NJiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>