reset: Fix and extend kerneldoc

Fix W=1 compile warnings (invalid kerneldoc):

    drivers/reset/core.c:50: warning: Function parameter or member 'array' not described in 'reset_control'
    drivers/reset/core.c:50: warning: Function parameter or member 'deassert_count' not described in 'reset_control'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>