V4L/DVB (13593): PWC: parameter trace is only available in debug

This patch fixes a small issue where modinfo says the parameter "trace" is always available, while
it only works if CONFIG_USB_PWC_DEBUG is enabled.
Signed-off-by: Andrea Odetti <mariofutire@googlemail.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/pwc/pwc-if.c

@@ -1947,7 +1947,9 @@ MODULE_PARM_DESC(size, "Initial image size. One of sqcif, qsif, qcif, sif, cif,
 MODULE_PARM_DESC(fps, "Initial frames per second. Varies with model, useful range 5-30");
 MODULE_PARM_DESC(fbufs, "Number of internal frame buffers to reserve");
 MODULE_PARM_DESC(mbufs, "Number of external (mmap()ed) image buffers");
+#ifdef CONFIG_USB_PWC_DEBUG
 MODULE_PARM_DESC(trace, "For debugging purposes");
+#endif
 MODULE_PARM_DESC(power_save, "Turn power save feature in camera on or off");
 MODULE_PARM_DESC(compression, "Preferred compression quality. Range 0 (uncompressed) to 3 (high compression)");
 MODULE_PARM_DESC(leds, "LED on,off time in milliseconds");