clk: samsung: Add MUX_FA macro to pass flag and alias

Cpufreq driver for some Samsung platforms have not yet been designed as
a platform driver, thereby they can only access clocks with an alias
name.

For EXYNOS4210, one such clock also requires a flag to be set, hence
there is a need to create another macro that can handle both flag and
alias.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>