staging: rtl8712: rename tmpVal to avg_val

staging: rtl8712: rename tmpVal to avg_val

Rename tmpVal to avg_val in process_link_qual() to reflect the intended use of
the variable and conform to the kernel coding style.

Signed-off-by: Ayush Tiwari <ayushtiw0110@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
Link: https://lore.kernel.org/r/ZfF+qu+CGHlpHrtY@ayush-HP-Pavilion-Gaming-Laptop-15-ec0xxx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>