ARM: OMAP: McSPI: handle clock enable / disable in omap2_mcspi

Enable / disable the mcspi_ick and mcspi_fck clocks in omap2_mcspi_probe
and omap2_mcspi_remove respectively.

Drop the ref count on the class device in omap2_mcspi_remove.

Change the clock names for mcspi_ick[123] and mcspi_fck[123] to mcspi_ick
and mcspi_fck, use instead the clk.id field for the bus id.

Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>