x86/signal: Add ABI prefixes to frame setup functions

Add ABI prefixes to the frame setup functions that didn't already have
them.  To avoid compiler warnings and prepare for moving these functions
to separate files, make them non-static.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/r/20220606203802.158958-7-brgerst@gmail.com


Signed-off-by: Borislav Petkov <bp@suse.de>