dmaengine: jz4740: Fix GPL v2 license string typo

Per license_is_gpl_compatible(), the MODULE_LICENSE() string for GPL v2 is
"GPL v2", not "GPLv2".  Use "GPL v2" so this module doesn't taint the
kernel.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dma-jz4740.c

@@ -614,4 +614,4 @@ module_platform_driver(jz4740_dma_driver);
 
 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 MODULE_DESCRIPTION("JZ4740 DMA driver");
-MODULE_LICENSE("GPLv2");
+MODULE_LICENSE("GPL v2");