nocturne: Change FIFO settings
nocturne: Change FIFO settings

Overly large sensor batches lead to timestamp synchronization
issues on Nocturne, causing - among others - CTS to sometimes
fail the sensor batching tests.

Reduce the size of the FIFO and restore the threshold to being
a third of the size. This value was changed in CL:1134494 in an
attempt to solve a problem which turned out to be unrelated.

BUG=b:117169255, b:73551961, b:120100420, b:120098451
BRANCH=nocturne
TEST=run CTS sensor test cases, observe them pass

Change-Id: Ia27bfe0a4756c22d4e48ba525d585ff11ab1cb63
Signed-off-by: Enrico Granata <f861e98f10aee98dc7dce70e80887ecdfdeb65b1@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1354484
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Tested-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>
Reviewed-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>

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