flash: jtagspi: fix clang build warning
Clang is unable to fully track the content of the array
write_buffer[] and incorrectly complains that it could contain
some uninitialized value.
To help clang to track the execution flow, rewrite the handling of
the buffer by using simpler indexing and by moving away cmd_byte
from the first buffer's element to the variable cmd_byte.
While there:
- fix the error codes returned while parsing the command line and
- use directly command_print_sameline() instead of passing through
intermediate buffers.
Change-Id: I1969e896887ea3a4abebee057cc04c03005fa57c
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7718
Tested-by: jenkins