The change fixes thread-local-storage size by removing .srodata section
from it. It initially was included in TLS section by mistake.
The issue was found when stack size increased after building applications
with GCC-11.1 compiler. Stack size became bigger because some new data
appeared in .srodata. See more details here:
adce62f53d
The CPU might prefetch instructions, which means it in some cases
will try to fetch instruction located after the last instruction in
flash.text.
Add dummy bytes to ensure fetching these wont result in an error,
e.g. MMU exceptions
