Every system call should be declared, so this adds missing
declarations for the ones we were missing so far.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

This is the complete set of new arch Score's files for linux.
Score instruction set support 16bits, 32bits and 64bits instruction,
Score SOC had been used in game machine and LCD TV.
Signed-off-by: NChen Liqin <liqin.chen@sunplusct.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>