dmaengine: imx-sdma: Only check ratio on parts that support 1:1

[Richard Leitner <richard.leitner@xxxxxxxxxxx>]

Please apply commit 941acd566b18 ("dmaengine: imx-sdma: Only check ratio 
on parts that support 1:1") to the 5.1 stable branch.

Without this patch following error message is issues when writing to 
UART 3 or UART 4 on an i.MX6 solo lite with Linux v5.1.4 (which fails).

	imx-sdma 20ec000.sdma: Timeout waiting for CH0 ready

The problem is fixed when applying this patch on v5.1.4 tag.

regards;Richard.L