[PATCH] i386: allow disabling X86_FEATURE_SEP at boot

Allow the x86 "sep" feature to be disabled at bootup.  This forces use of the
int80 vsyscall.  Mainly for testing or benchmarking the int80 vsyscall code.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>