Documentation: charger: max14577: Update the date of introducing ABI

Update the date of introducing max14577 charger's ABI (fast_charge_timer
sysfs entry) to approximate date of kernel release which actually
introduces this.

The old date came from previous driver submissions.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>