i2c: mxs: suppress probe-deferral error message

During boot of I2SE Duckbill the kernel log contains a
confusing error:

  Failed to request dma

This is caused by i2c-mxs tries to request a not yet available DMA
channel (-EPROBE_DEFER). So suppress this message by using
dev_err_probe().

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>