ec: Remove calls to __gcov_flush
ec: Remove calls to __gcov_flush

__gcov_flush was removed in GCC 11, and apparently it is the same as
calling dump and then reset, so switch to that.

BRANCH=None
BUG=None
TEST=make TEST_FLAG=TEST_COVERAGE=y \
  build/coverage/usb_pe_drp_noextended.info
TEST=make TEST_FLAG=TEST_COVERAGE=y CC=clang \
  build/coverage/usb_pe_drp_noextended.info
TEST=(in docker) make -j8 CRYPTOC_DIR="${MODULES_DIR}/cryptoc" \
  HOSTGCOV='gcov' \
  CROSS_COMPILE_arm=/opt/zephyr-sdk/arm-zephyr-eabi/bin/arm-zephyr-eabi- \
  TEST_FLAG=TEST_COVERAGE=y build/coverage/usb_pe_drp_noextended.info

Signed-off-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@google.com>
Change-Id: I9f0c8732126104c056b6adb82e4c0a1b78ac1d3e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3818124
Tested-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Commit-Queue: Tristan Honscheid <1e17951ff5ffc8afe254954c03de64afef62fe52@google.com>
Reviewed-by: Tristan Honscheid <1e17951ff5ffc8afe254954c03de64afef62fe52@google.com>
Code-Coverage: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Auto-Submit: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>

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