dmaengine: dw-edma: fix unnecessary stack usage

Putting large constant data on the stack causes unnecessary overhead
and stack usage:

drivers/dma/dw-edma/dw-edma-v0-debugfs.c:285:6: error: stack frame size of 1376 bytes in function 'dw_edma_v0_debugfs_on' [-Werror,-Wframe-larger-than=]

Mark the variable 'static const' in order for the compiler to move it
into the .rodata section where it does no such harm.

Fixes: 305aebef ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/20190722124457.1093886-1-arnd@arndb.deSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/dw-edma/dw-edma-v0-debugfs.c

@@ -48,7 +48,7 @@ static struct {
 } lim[2][EDMA_V0_MAX_NR_CH];
 
 struct debugfs_entries {
-	char					name[24];
+	const char				*name;
 	dma_addr_t				*reg;
 };