[MIPS] Always do the ARC64_TWIDDLE_PC thing.

Always jump to the place where the kernel is linked to. This helps where
the bootloaders/proms ignores the start address inside the ELF header.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>