In fd233832ef
the linker flag -lgcc might not work on EON as it does not have the
correct library.
The fix was a workaround in sha.c such that we no longer need to import
function __aeabi_llsr from library, by replacing right shift operation
with const argument.
E.g.,
uint64_t a = b >> i // requires __aeabi_llsr from libgcc
uint64_t a = b >> 2 // does not require external library
Resolves: #522
dekerr