MIPS: Ingenic: Add system type for new Ingenic SoCs.

Add JZ4775, X1000E, X2000, and X2000E system type for cat /proc/cpuinfo
to give out JZ4775, X1000E, X2000 and X2000E.

Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>