i2c: stm32: fix error message on upon dma_request_chan & defer handling

DMA usage is optional for the I2C driver. check for the -ENODEV
error in order to avoid displaying an error when no DMA
has been requested.
Cleaning up the error messages during probe, remove the additional
-EPROBE_DEFER within probe function since additional error message
doesn't give much more information than what is already reported
within the stm32_i2c_dma_request function.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2 files changed