V4L2 will disable strobe mode of the LED device when enable torch mode,
but this logic will conflict with the "priv->fled_torch_used"
in "mt6360_strobe_set()". So after enabling torch mode of the first
LED, the second LED will not be able to enable torch mode correctly.

Therefore, at the beginning of "mt6360_strobe_set()", check whether the
state of the upcoming change and the current LED device state are the
same, so as to avoid the above problem.
Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
Link: https://lore.kernel.org/r/28FE6F1712799128000.chiaen_wu@richtek.comSigned-off-by: Lee Jones <lee@kernel.org>