cpufreq: expose a cpufreq_quick_get_max routine

This allows drivers and other code to get the max reported CPU frequency.
Initial use is for scaling ring frequency with GPU frequency in the i915
driver.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
Revert "fs: skip read-only remount of mmcblk0p19"

This reverts commit 7c6c31212f8e9ecf31784f57fac7c5d6b510c4ff.