clk: mmp: pxa1928: drop unused 'clk' variable

clk: mmp: pxa1928: drop unused 'clk' variable

'clk' is assigned but never read:

  drivers/clk/mmp/clk-of-pxa1928.c: In function ‘pxa1928_pll_init’:
  drivers/clk/mmp/clk-of-pxa1928.c:71:14: warning: variable ‘clk’ set but not used [-Wunused-but-set-variable]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200916161740.14173-4-krzk@kernel.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>