clk: ti: add new API for checking if a provided clock is an OMAP clock

omap2_clk_is_hw_omap can now be used to verify if the provided clk_hw
is an omap HW clock or not. This is done to replace the usage of CLK_IS_BASIC
flag within the TI clock drivers.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Keerthy <j-keerthy@ti.com>