ACPICA: Debugger: Remove some unecessary NULL checks

ACPICA commit 36fcc1b98def3fb6e20cf5e877ffc3c1592d0140

Local strupr function already checks for NULL pointers.

Original linux patch submitted by:
Markus Elfring <elfring@users.sourceforge.net>

Link: https://github.com/acpica/acpica/commit/36fcc1b9


Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>