dt-bindings: mfd: ti,bq25703a: Expand to include BQ25792

dt-bindings: mfd: ti,bq25703a: Expand to include BQ25792

TI BQ25792 is similar in operation to BQ25703A, but has a different
register layout and different current/voltage capabilities.

Expand the existing BQ25703A binding to include BQ25792, and move the
voltage and current limits into per-variant conditional statements.

Signed-off-by: Alexey Charkov <alchark@flipper.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Tested-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://patch.msgid.link/20260331-bq25792-v6-1-0278fba33eb9@flipper.net
Signed-off-by: Lee Jones <lee@kernel.org>