Cortex M33 support

Hi Juan,

thanks for pointing out: I'll try and check with our contacts to NXP.

Best,   Thomas

FYI, Microchip sent me a SAML10 and a SAML11 (Cortex-M23) Xplained boards so I can port them to RIOT. Yesterday I was able to run tests/leds on SAML10, but it is still too early to share my ugly hacked code. As I saw we can reuse cortexm_common stuff because armv8-M baseline and mainline instructions set are 100% compatible with armv6-M instructions set. But I found out some bits disappeared from some registers like SCB_CCR_STKALIGN bit.

I also think it would be great to support brand new ARM MCU out-of-box !