arm: am57xx: cl-som-am57x: Use new pinctrl macros

Commit 6ae4c3ef ("ARM: DRA7: Add pinctrl register definitions")
has added new macros for pinmux configuration in line with the
kernel definitions. Fixup the current pinctrl data for the CompuLab
CL-SOM-AM57x board to use these new macros to facilitate the removal
of the old macros.

NOTE:
The PEN and PDIS macro values used previously were actually defined
inversely, a value of 1 in bit position 16 actually means that the
internal pullup/pulldown is disabled and not enabled as inferred by
PEN. So, previous pinmux config data such as (PDIS | PTU) is confusing
as it actually was meant for enabling internal pullup. The data is
fixed up only to be equivalent to the previous data.

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