stm32g4: Add clock enable logic for HW timer
stm32g4: Add clock enable logic for HW timer

This CL adds clock enable support for stm32g4 family.

BUG=b:148493929
BRANCH=None
TEST=verfied that via scope that led toggle happens at 1 second window
when using one second hook call.

Signed-off-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@google.com>
Change-Id: Ie3d353ec40206e93cfac7b8738166ffee6c8442c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2195548
Tested-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Commit-Queue: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Reviewed-by: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>

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