dmaengine: sa11x0: use correct print specifiers for size_t

This driver when compiled on 64 bits gave warnings:

drivers/dma/sa11x0-dma.c:602:2: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 6 has type ‘size_t’ [-Wformat=]

We should use %zu to print 'size_t' values.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>