tegra124: Add a test function which spams exclamation points on the UART.

This function spews characters on the console and, until we have a working
console, is an easy way to see whether the system boots to a particular point.
For some reason waiting for transmitter to be empty hangs, but transmitting
characters still works.

TEST=Enabled the function and saw the UART output.

Change-Id: I1622c8a58849f4b8bdcaa67500b81042d7346df4
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://chromium-review.googlesource.com/171030
Reviewed-by: Ronald Minnich <rminnich@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
1 file changed