clk: mux: remove redundant initialization of variable width

Variable width is being ininitialized with a value that is never read.
The ininitializtion is redundant and can be removed. Move the variable
to the scope it is required.

Cleans up cppcheck warning:
Variable 'width' is assigned a value that is never used.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220424182227.1364966-1-colin.i.king@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>