USB: serial mct_usb232: move DMA buffers to heap

My distro kernel (Fedora Rawhide) started throwing warnings from DMA API
checker, so I have no choice but band-aid it quick. There's no attempt
to reuse DMA buffers. Control messages are only sent rarely anyway.

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


diff --git a/drivers/usb/serial/mct_u232.h b/drivers/usb/serial/mct_u232.h
index 07b6bec..7417d5c 100644
--- a/drivers/usb/serial/mct_u232.h
+++ b/drivers/usb/serial/mct_u232.h
@@ -73,6 +73,8 @@
 #define MCT_U232_SET_CTS_REQUEST   12
 #define MCT_U232_SET_CTS_SIZE       1
 
+#define MCT_U232_MAX_SIZE		4	/* of MCT_XXX_SIZE */
+
 /*
  * Baud rate (divisor)
  * Actually, there are two of them, MCT website calls them "Philips solution"