usb: linux/usb/pd_vdo.h: drop duplicated word in comment

Drop the doubled word "all" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20200715045701.22949-3-rdunlap@infradead.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/usb/pd_vdo.h

@@ -249,7 +249,7 @@
  * SVDM Discover SVIDs request -> response
  *
  * Request is properly formatted VDM Header with discover SVIDs command.
- * Response is a set of SVIDs of all all supported SVIDs with all zero's to
+ * Response is a set of SVIDs of all supported SVIDs with all zero's to
  * mark the end of SVIDs.  If more than 12 SVIDs are supported command SHOULD be
  * repeated.
  */