spi: atmel: Silence checkpatch errors

Fixes the following types of checkpatch errors and warning:
ERROR: space required after that ',' (ctx:VxV)
WARNING: sizeof *as should be sizeof(*as)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>