dmaengine: dw-edma: Rename debugfs dentry variables to 'dent'

Since we are about to add the eDMA channels direction support to the
debugfs module it will be confusing to have both the debugfs directory and
the channels direction short names used in the same code.

Rename the debugfs dentry 'dir' variables to 'dent' to prevent confusion.

Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20230113171409.30470-15-Sergey.Semin@baikalelectronics.ru


Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>