thermal/drivers/k3_j72xx_bandgap: Fix array underflow in prep_lookup_table()

This while loop exits with "i" set to -1 and so then it sets:

	derived_table[-1] = derived_table[0] - 300;

There is no need for this assignment at all.  Just delete it.

Fixes: 72b3fc61c752 ("thermal: k3_j72xx_bandgap: Add the bandgap driver support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YoetjwcOEzYEFp9b@kili


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>