arm64: dts: meson: set 128bytes FIFO size on uart A

The first UART controller in "Everything-Else" power domain, usually used
for Bluetooth HCI has 128bytes FIFO depth.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20210518075833.3736038-4-narmstrong@baylibre.com