dmaengine: pxa_dma: fix debug information

This fixes the following error:
drivers/dma/pxa_dma.c: In function ‘dbg_show_requester_chan’:
drivers/dma/pxa_dma.c:192:2: error: void value not ignored as it ought to be
  pos += seq_printf(s, "DMA channel %d requester :\n", phy->idx);
  ^
drivers/dma/pxa_dma.c:197:8: error: void value not ignored as it ought to be
        !!(drcmr & DRCMR_MAPVLD));
        ^
scripts/Makefile.build:258: recipe for target 'drivers/dma/pxa_dma.o' failed

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>