flash/stm32l4x: add support of STM32U57x/U58x

flash/stm32l4x: add support of STM32U57x/U58x

this device flash registers are quite similar to STM32L5
with this changes :
 - flash size is up to 2MB
 - 2MB variants are always dual bank
 - 1MB and 512KB variants could be dual bank (contiguous addressing)
   depending on DUALBANK bit(21)
 - flash data width is 16 bytes (quad-word)

Change-Id: Id13c552270ce1071479ad418526e8a39ebe83cb1
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6108
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>