arm64: defconfig: Enable Qualcomm PON driver

The PON block in the PMIC provides, among other things, support for
"reboot reason", power key and reset "key" handling. Let's enable the
driver for this block.

Reviewed-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20201125023831.99774-1-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>