am335x evm: Initial support for AM335x GP EVM Profiles

The AM335x GP EVM can have one of 8 different profiles selected.  Each
profile has a different set of peripherals and requires different pinmux
configurations that conflict with other profiles.  i2c1 is an example of
a conflicted mux currently.

Signed-off-by: Tom Rini <trini@ti.com>