Since there are multiple controllers in the LPSS and all use the same
frequency, provide a single Kconfig option for LPSS_CLOCK_MHZ.
BUG=b:35583330
Change-Id: I3c0cb62d56916e6e5f671fb5f40210f4cb33316f
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/19115
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)