microblaze: use asm-generic for seccomp.h

microblaze: use asm-generic for seccomp.h

Switch to using the newly created asm-generic/seccomp.h for the seccomp
strict mode syscall definitions. Since microblaze is 32-bit, the COMPAT
seccomp defines are unused and can be dropped. The obsolete sigreturn
for seccomp strict mode is retained as an override. Remaining definitions
are identical.

Signed-off-by: Kees Cook <[email protected]>
Cc: Michal Simek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>