ASoC: renesas: rz-ssi: Add a check for negative sample_space

My static checker rule complains about this code.  The concern is that
if "sample_space" is negative then the "sample_space >= runtime->channels"
condition will not work as intended because it will be type promoted to a
high unsigned int value.

strm->fifo_sample_size is SSI_FIFO_DEPTH (32).  The SSIFSR_TDC_MASK is
0x3f.  Without any further context it does seem like a reasonable warning
and it can't hurt to add a check for negatives.

Cc: stable@vger.kernel.org
Fixes: 03e786bd ("ASoC: sh: Add RZ/G2L SSIF-2 driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/e07c3dc5-d885-4b04-a742-71f42243f4fd@stanley.mountain


Signed-off-by: Mark Brown <broonie@kernel.org>