hw/arm/omap1:Remove redundant statement in omap_clkdsp_read()

hw/arm/omap1:Remove redundant statement in omap_clkdsp_read()

Clang static code analyzer show warning:
hw/arm/omap1.c:1760:15: warning: Value stored to 'cpu' during its
initialization is never read
    CPUState *cpu = CPU(s->cpu);
              ^~~   ~~~~~~~~~~~

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Message-Id: <20200827110311.164316-3-kuhn.chenqun@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>