macintosh/via-macii: Clarify definition of macii_init()

The function prototype correctly specifies the 'static' storage class.
Let the function definition match the declaration for better readability.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c025aed0b1506399b73ff1d1bfa40ed641fcb3e3.1593318192.git.fthain@telegraphics.com.au