flash/nor/stm32f1x: lock flash in case of error

flash/nor/stm32f1x: lock flash in case of error

The current code locks the flash controller in case of error during
flash write only. An error in other flash operations may cause the
flash is left unlocked.

Implement locking also after error in erase, mass erase, options
write and erase.

Change-Id: I26c2ed7914e7847122306f29b777b9eefd1dc580
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/6710
Tested-by: jenkins
Reviewed-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>