dmaengine: remove debugfs #ifdef

dmaengine: remove debugfs #ifdef

The ptdma driver has added debugfs support, but this fails to build
when debugfs is disabled:

drivers/dma/ptdma/ptdma-debugfs.c: In function 'ptdma_debugfs_setup':
drivers/dma/ptdma/ptdma-debugfs.c:93:54: error: 'struct dma_device' has no member named 'dbg_dev_root'
   93 |         debugfs_create_file("info", 0400, pt->dma_dev.dbg_dev_root, pt,
      |                                                      ^
drivers/dma/ptdma/ptdma-debugfs.c:96:55: error: 'struct dma_device' has no member named 'dbg_dev_root'
   96 |         debugfs_create_file("stats", 0400, pt->dma_dev.dbg_dev_root, pt,
      |                                                       ^
drivers/dma/ptdma/ptdma-debugfs.c:102:52: error: 'struct dma_device' has no member named 'dbg_dev_root'
  102 |                 debugfs_create_dir("q", pt->dma_dev.dbg_dev_root);
      |                                                    ^

Remove the #ifdef in the header, as this only saves a few bytes,
but would require ugly #ifdefs in each driver using it.
Simplify the other user while we're at it.

Fixes: e2fb2e2a33fa ("dmaengine: ptdma: Add debugfs entries for PTDMA")
Fixes: 26cf132de6f7 ("dmaengine: Create debug directories for DMA devices")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20210920122017.205975-1-arnd@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>