misc: mic: host: mic_x100: Add missing descriptions to kerneldoc headers

misc: mic: host: mic_x100: Add missing descriptions to kerneldoc headers

Fixes the following W=1 warnings:

 drivers/misc/mic/host/mic_x100.c:127: warning: Function parameter or member 'doorbell' not described in 'mic_x100_send_sbox_intr'
 drivers/misc/mic/host/mic_x100.c:148: warning: Function parameter or member 'doorbell' not described in 'mic_x100_send_rdmasr_intr'
 drivers/misc/mic/host/mic_x100.c:511: warning: Function parameter or member 'dma_addr' not described in 'mic_x100_smpt_set'
 drivers/misc/mic/host/mic_x100.c:511: warning: Function parameter or member 'index' not described in 'mic_x100_smpt_set'

Cc: Sudeep Dutt <sudeep.dutt@intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200701083118.45744-13-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>