mmc: core: Update target-frequency while resuming clock scaling

The frequency comparison in clock scaling while setting the target
frequency was changed from current-frequency to target-frequency
against the requested frequency by the commit <3a6f149d>
("mmc: core: Use new flag for suspending clk scaling").

When clock scaling is disabled and re-enabled, current-frequency
gets updated to max frequency but target-frequency remains at its
old value. Due to this clock is not scaling down and causing power
regressions.

To fix this issue, updating the target-frequency with the current-
frequency during clock scaling resume.

Change-Id: Ia033542724aac1f77f2dfbde0d9784e4c0657844
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>