mei: use kvmalloc for read buffer

Read buffer is allocated according to max message size, reported by
the firmware and may reach 64K in systems with pxp client.
Contiguous 64k allocation may fail under memory pressure.
Read buffer is used as in-driver message storage and not required
to be contiguous.
Use kvmalloc to allow kernel to allocate non-contiguous memory.

Fixes: 3030dc056459 ("mei: add wrapper for queuing control commands.")
Cc: stable <[e-mail]>
Reported-by: Rohit Agarwal <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Tested-by: Brian Geffon <[e-mail]>
Signed-off-by: Alexander Usyskin <[e-mail]>
Acked-by: Tomas Winkler <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mei/client.c

···
 		return;
 
 	list_del(&cb->list);
-	kfree(cb->buf.data);
+	kvfree(cb->buf.data);
 	kfree(cb->ext_hdr);
 	kfree(cb);
 }
···
 	if (length == 0)
 		return cb;
 
-	cb->buf.data = kmalloc(roundup(length, MEI_SLOT_SIZE), GFP_KERNEL);
+	cb->buf.data = kvmalloc(roundup(length, MEI_SLOT_SIZE), GFP_KERNEL);
 	if (!cb->buf.data) {
 		mei_io_cb_free(cb);
 		return NULL;