driver: bm160: Fix minimal gyro frequency
driver: bm160: Fix minimal gyro frequency

Was set in Hz unit instead of mHz.
The minimal frequency of the gyroscope is 25Hz.
By setting it at 25mHz, we make believe that the gyro was also
supporting 5Hz or 10Hz: the test would complain when instead the samples
came with a 25Hz.

Fix up of cl/482703

BUG=b:65000611
TEST=compile
BRANCH=caroline,eve,twinkie

Change-Id: I162d0d2e9b545af82698d8d484875761f426efe4
Signed-off-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/674003
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec