hurd: Move a couple of signal-related files to x86

These do not need any changes to be used on x86_64.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230319151017.531737-20-bugaevc@gmail.com>

diff --git a/sysdeps/mach/hurd/i386/exc2signal.c b/sysdeps/mach/hurd/x86/exc2signal.c
similarity index 100%
rename from sysdeps/mach/hurd/i386/exc2signal.c
rename to sysdeps/mach/hurd/x86/exc2signal.c

diff --git a/sysdeps/mach/hurd/i386/signal-defines.sym b/sysdeps/mach/hurd/x86/signal-defines.sym
similarity index 100%
rename from sysdeps/mach/hurd/i386/signal-defines.sym
rename to sysdeps/mach/hurd/x86/signal-defines.sym