davinci: Move PINMUX defines to SoC files

Different SoC have different numbers of pinmux registers and other
resources that overlap with each other.  To clean up the code and
eliminate defines that overlap with each other, move the PINMUX
defines to the SoC specific files.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>