of: device: Fix function name in header and provide missing descriptions

Fixes the following W=1 kernel build warning(s):

 drivers/of/device.c:72: warning: expecting prototype for of_dma_configure(). Prototype was for of_dma_configure_id() instead
 drivers/of/device.c:263: warning: Function parameter or member 'dev' not described in 'of_device_modalias'
 drivers/of/device.c:263: warning: Function parameter or member 'str' not described in 'of_device_modalias'
 drivers/of/device.c:263: warning: Function parameter or member 'len' not described in 'of_device_modalias'
 drivers/of/device.c:280: warning: Function parameter or member 'dev' not described in 'of_device_uevent'
 drivers/of/device.c:280: warning: Function parameter or member 'env' not described in 'of_device_uevent'

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210318104036.3175910-2-lee.jones@linaro.org