clk: samsung: exynos5410: Add serial3, USB and PWM clocks

Just like other Exynos5 family SoCs, this one has four UARTs. Add
missing UART3 clocks to the Exynos5410 clock driver.

Add clocks for USB and PWM.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>