mips: sync asm/mipsregs.h with Linux 5.7

Sync asm/mipsregs.h with Linux 5.7. Also replace the custom
symbols EBASE_CPUNUM and EBASE_WG with the according symbols
from Linux.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>
5 files changed