drm/modes: Use strscpy() to copy command-line mode name

The mode name in struct drm_cmdline_mode can hold 32 characters at most,
which can easily get overrun. Switch to strscpy() to prevent such a
thing.
Reported-by: Ncoverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527354 ("Security best practices violations")
Fixes: a7ab1553 ("drm/modes: Switch to named mode descriptors")
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20221128081938.742410-2-maxime@cerno.techSigned-off-by: NMaxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/drm_modes.c

@@ -2316,7 +2316,7 @@ static int drm_mode_parse_cmdline_named_mode(const char *name,
 		if (ret != name_end)
 			continue;
 
-		strcpy(cmdline_mode->name, mode->name);
+		strscpy(cmdline_mode->name, mode->name, sizeof(cmdline_mode->name));
 		cmdline_mode->pixel_clock = mode->pixel_clock_khz;
 		cmdline_mode->xres = mode->xres;
 		cmdline_mode->yres = mode->yres;