OMAP4: clock data: Remove McASP2, McASP3 and MMC6 clocks

McASP2, 3 and MMC6 modules are not present in the OMAP4 family.
Remove the fclk and the clksel related to these nodes.
Rename the references that were potentially re-used in order nodes.

Remove related macros in prcm header files.

Update TI copyright date.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
[b-cousson@ti.com: Update the patch according to autogen output]
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
[paul@pwsan.com: split PRCM data changes into a separate patch]
Signed-off-by: Paul Walmsley <paul@pwsan.com>