ARM: dts: am437x-gp-evm: Do not reset gpio5

Do not reset GPIO5 at boot-up because GPIO5_7 is used
on AM437x GP-EVM to control VTT regulators on DDR3.
Without this some GP-EVM boards will fail to boot because
of DDR3 corruption.

Reported-by: Nishanth Menon <nm@ti.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>