Depending on initial size allocated on STM32L4 devices with
TWO_RAM_REGIONS set a crash may occur. This is because there is a
mismatch between the size newlib is expecting and the size actually
returned by _sbrk. This is because the STM32L4 implementation of _sbrk
is performing alignment internally.
This patch fixes this problem by removing the code in __wrap__sbrk
which performs the alignment.