dmaengine: drivers: Kconfig: add HAS_IOMEM dependency to DW_AXI_DMAC

If HAS_IOMEM is not defined and DW_AXI_DMAC is enabled under COMPILE_TEST,
the build fails with the following error:
dw-axi-dmac-platform.c:(.text+0xc4): undefined reference to
`devm_ioremap_resource'
Link: https://www.spinics.net/lists/dmaengine/msg25188.html

Reported-by: kernel test robot <[e-mail]>
Signed-off-by: Sia Jee Heng <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/Kconfig

···
 config DW_AXI_DMAC
 	tristate "Synopsys DesignWare AXI DMA support"
 	depends on OF || COMPILE_TEST
+	depends on HAS_IOMEM
 	select DMA_ENGINE
 	select DMA_VIRTUAL_CHANNELS
 	help