package/libsigrokdecode: needs python3 w/ zlib support

Some protocol decoders in libsigrokdecode need the zlib module:

    srd: ModuleNotFoundError: Failed to load decoder usb_power_delivery: import by name failed: No module named 'zlib'
    srd: Traceback (most recent call last):
      File "/usr/share/libsigrokdecode/decoders/usb_power_delivery/__init__.py", line 24, in <module>
        from .pd import *
      File "/usr/share/libsigrokdecode/decoders/usb_power_delivery/pd.py", line 24, in <module>
        import zlib   # for crc32
        ^^^^^^^^^^^
    ModuleNotFoundError: No module named 'zlib'

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 9d6ab1244a3d8b9c4934caf9cf7810086de7c82f)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/libsigrokdecode/Config.in

@@ -6,6 +6,7 @@ config BR2_PACKAGE_LIBSIGROKDECODE
 	depends on !BR2_STATIC_LIBS # python3
 	select BR2_PACKAGE_LIBGLIB2
 	select BR2_PACKAGE_PYTHON3
+	select BR2_PACKAGE_PYTHON3_ZLIB  # runtime
 	help
 	  Libsigrokdecode is a shared library written in C, which
 	  provides (streaming) protocol decoding functionality. Say