staging: unisys: fix CamelCase local in textid functions

Fix the CamelCased local variable

textId => text_id

In both of the textid sysfs functions, and update all references to use the
corrected name.

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>