mmc: sdhci: Fix sdhci_runtime_pm_bus_on/off()

sdhci has a legacy facility to prevent runtime suspend if the
bus power is on.  This is needed in cases where the power to
the card is dependent on the bus power.  It is controlled by
a pair of functions: sdhci_runtime_pm_bus_on() and
sdhci_runtime_pm_bus_off().  These functions use a boolean
variable 'bus_on' to ensure changes are always paired.
There is an additional check for 'runtime_suspended' which is
the problem.  In fact, its use is ill-conceived as the only
requirement for the logic is that 'on' and 'off' are paired,
which is actually broken by the check, for example if the bus
power is turned on during runtime resume.  So remove  the check.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v3.11+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>