ARM: dts: dra7x-evm: avoid possible contention while muxing on CAN lines

DCAN1 RX and TX lines are internally pulled high according to [1].
While muxing between DCAN mode and SAFE mode we make sure
that the same pull direction is set to minimize opposite
pull contention during the switching window.

[1] in DRA7 data manual, Ball characteristics table 4-2, DSIS colum shows
the state driven to the peripheral input while in the deselcted mode.
DSIS - De-Selected Input State.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>