mfd: rave-sp: Fix mistake in 'struct rave_sp_deframer's kerneldoc

Argument 'received' was incorrectly named by its struct type 'completion'
instead of its name.

Fixes the following W=1 warning:

 drivers/mfd/rave-sp.c:107: warning: Function parameter or member 'received' not described in 'rave_sp_reply'

Cc: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>