um: stub_rt_sigsuspend isn't needed these days anymore

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/x86/um/sys_call_table_64.c

@@ -31,7 +31,6 @@
 #define stub_fork sys_fork
 #define stub_vfork sys_vfork
 #define stub_execve sys_execve
-#define stub_rt_sigsuspend sys_rt_sigsuspend
 #define stub_sigaltstack sys_sigaltstack
 #define stub_rt_sigreturn sys_rt_sigreturn