gitlab: Set the fpu flags correctly
gitlab: Set the fpu flags correctly

Use the zephyr_cc_option function instead of modifying CMAKE vars.

BUG=b:178731498
TEST=zmake testall in docker container
BRANCH=None

Signed-off-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@google.com>
Change-Id: I97e6481e9ba3fb865e7ad49e029dfa50731a7fe6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3140779
Commit-Queue: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Tested-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@chromium.org>

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