thunderbolt: Fix one kernel-doc comment

Fix a spelling errors in kernel doc comment, silence the warning:

drivers/thunderbolt/tb.c:760: warning: expecting prototype for tb_maximum_banwidth(). Prototype was for tb_maximum_bandwidth() instead

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7048


Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>