ARM: dts: dra72-evm: Rename 3.3V regulator tag

Rename the tag of the 3.3 V regulator used in the DRA72 EVM in
order to have a consistent tag name with the DRA7 EVM.  This
is useful when the regulator needs to be referenced in common
dtsi files (i.e. for common companion boards like JAMR3 [1]).

[1] http://www.ti.com.cn/cn/lit/ug/sprui52/sprui52.pdf



Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>