riscv: dts: allwinner: rename devterm i2c-gpio node to comply with binding

The i2c controller binding does not permit permit the node name to
contain "gpio", resulting in two warnings:

i2c-gpio-0 (i2c-gpio): $nodename:0: 'i2c-gpio-0' does not match '^i2c(@.+|-[a-z0-9]+)?$'
i2c-gpio-0 (i2c-gpio): Unevaluated properties are not allowed ('#address-cells', '#size-cells', 'adc@54' were unexpected)

Drop it to satisfy dtbs_check.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20250909-frown-wrinkle-f16df243a970@spud


Signed-off-by: Chen-Yu Tsai <wens@csie.org>