staging: most: dim2: Add missing identifier name to function argument

staging: most: dim2: Add missing identifier name to function argument

A function definition argument should have an identifier name according
to checkpatch:

WARNING: function definition argument 'struct platform_device *' should
also have an identifier name

Name it pdev as that name is already used throughout the code.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20200802223615.924307-1-nfraprado@protonmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>