scripts: get_abi.pl: create a valid ReST with duplicated tags

As warned, /sys/bus/iio/devices/iio:deviceX/fault_ovuv is defined 2 times:

	Warning: /sys/bus/iio/devices/iio:deviceX/fault_ovuv is defined 2 times:  ./Documentation/ABI/testing/sysfs-bus-iio-temperature-max31856:14  ./Documentation/ABI/testing/sysfs-bus-iio-temperature-max31865:0

The logic with joins the two entries is just places the paragraph
for the second entry after the previous one. That could cause more
warnings, as the produced ReST may become invalid, as in the case of
this specific symbol, which ends with a table:

	/new_devel/v4l/docs/Documentation/ABI/testing/sysfs-bus-iio-temperature-max31856:2: WARNING: Malformed table.
	No bottom table border found or no blank line after table bottom.

	===  =======================================================
	'1'  The input voltage is negative or greater than VDD.
	'0'  The input voltage is positive and less than VDD (normal
	     state).
	===  =======================================================
	/new_devel/v4l/docs/Documentation/ABI/testing/sysfs-bus-iio-temperature-max31856:2: WARNING: Blank line required after table.

Address it by adding two blank lines before joining duplicated
symbols.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/4ad2e3a65f781f0f8d40bb75aa5a07aca80564d6.1632740376.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/get_abi.pl

@@ -180,6 +180,7 @@ sub parse_abi {
 						$data{$what}->{file} = $name;
 						$data{$what}->{filepath} = $file;
 					} else {
+						$data{$what}->{description} .= "\n\n" if (defined($data{$what}->{description}));
 						if ($name ne $data{$what}->{file}) {
 							$data{$what}->{file} .= " " . $name;
 							$data{$what}->{filepath} .= " " . $file;