ARM: DRA7: Cleanup old pinctrl macros

Commit 6ae4c3ef ("ARM: DRA7: Add pinctrl register definitions")
has added new macros for pinmux configuration in line with the kernel
definitions. Cleanup the old pinctrl macros from the common header
file so that they are not used by any new boards.

Signed-off-by: Suman Anna <s-anna@ti.com>