docs: ABI: testing: iio: stm32: remove re-introduced unsupported ABI

Remove unsupported ABI that has been re-introduced due to a rebase hunk.
This ABI has been moved in the past in commit b299d004
("IIO: stm32: Remove quadrature related functions from trigger driver")

This also fixes a couple of warnings seen with:
./scripts/get_abi.pl validate 2>&1|grep iio

Fixes: 34433332 ("docs: ABI: testing: make the files compatible with ReST output")
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Link: https://lore.kernel.org/r/1604685016-2434-1-git-send-email-fabrice.gasnier@st.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-iio-timer-stm32

@@ -109,30 +109,6 @@ Description:
 		When counting down the counter start from preset value
 		and fire event when reach 0.
 
-What:		/sys/bus/iio/devices/iio:deviceX/in_count_quadrature_mode_available
-KernelVersion:	4.12
-Contact:	benjamin.gaignard@st.com
-Description:
-		Reading returns the list possible quadrature modes.
-
-What:		/sys/bus/iio/devices/iio:deviceX/in_count0_quadrature_mode
-KernelVersion:	4.12
-Contact:	benjamin.gaignard@st.com
-Description:
-		Configure the device counter quadrature modes:
-
-		channel_A:
-			Encoder A input servers as the count input and B as
-			the UP/DOWN direction control input.
-
-		channel_B:
-			Encoder B input serves as the count input and A as
-			the UP/DOWN direction control input.
-
-		quadrature:
-			Encoder A and B inputs are mixed to get direction
-			and count with a scale of 0.25.
-
 What:		/sys/bus/iio/devices/iio:deviceX/in_count_enable_mode_available
 KernelVersion:	4.12
 Contact:	benjamin.gaignard@st.com