OMAP4: Clocks: Change SPI Instance Names

Change the name for the spi instances on omap44xx_clks to match
the names omap2 spi driver gives:

omap-mcspi.1 -> omap2_mcspi.1
omap-mcspi.2 -> omap2_mcspi.2
omap-mcspi.3 -> omap2_mcspi.3
omap-mcspi.4 -> omap2_mcspi.4

Signed-off-by: Abraham Arce <x0066660@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>