check correct bootloader address

[josecostamartins]

find correct version to put on this file: https://github.com/josecostamartins/qmk_firmware/blob/anne_pro/keyboards/anne_pro/bootloader_defs.h

Based on http://www.st.com/web/en/resource/technical/document/application_note/CD00167594.pdf the bootloader addres should be 0x1FF00000, but that should be further investigated.

The reference manual (http://www.st.com/content/ccc/resource/technical/document/reference_manual/cc/f9/93/b2/f0/82/42/57/CD00240193.pdf/files/CD00240193.pdf/jcr:content/translations/en.CD00240193.pdf) apparently does not show anything of use from the bootloader (but that should be investigated further also)