dmaengine: idma: rename to INTEL_IDMA64

the symbol CONFIG_IDMA64 should rather be CONFIG_INTEL_IDMA64 to conform to
rest of the intel dmaengine drivers. This was found after sorting the
entries and trying to place this odd one

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>