arm64: dts: allwinner: Fix SD card CD GPIO for SOPine systems

Commit 941432d0 ("arm64: dts: allwinner: Drop non-removable from
SoPine/LTS SD card") enabled the card detect GPIO for the SOPine module,
along the way with the Pine64-LTS, which share the same base .dtsi.

However while both boards indeed have a working CD GPIO on PF6, the
polarity is different: the SOPine modules uses a "push-pull" socket,
which has an active-high switch, while the Pine64-LTS use the more
traditional push-push socket and the common active-low switch.

Fix the polarity in the sopine.dtsi, and overwrite it in the LTS
board .dts, to make the SD card work again on systems using SOPine
modules.

Fixes: 941432d0 ("arm64: dts: allwinner: Drop non-removable from SoPine/LTS SD card")
Reported-by: Ashley <contact@victorianfox.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210316144219.5973-1-andre.przywara@arm.com