package: propagate pulseaudio dependencies correctly

The BR2_PACKAGE_PULSEAUDIO_HAS_ATOMIC dependency of
BR2_PACKAGE_PULSEAUDIO was not properly propagated to reverse
dependencies, causing the following kconfig warning:

warning: (BR2_PACKAGE_ESPEAK_AUDIO_BACKEND_PULSEAUDIO && BR2_PACKAGE_GST_PLUGINS_GOOD_PLUGIN_PULSE && BR2_PACKAGE_GST1_PLUGINS_GOOD_PLUGIN_PULSE && BR2_PACKAGE_KODI_PULSEAUDIO && BR2_PACKAGE_MPD_PULSEAUDIO && BR2_PACKAGE_EFL_PULSEAUDIO) selects BR2_PACKAGE_PULSEAUDIO which has unmet direct dependencies (BR2_PACKAGE_PULSEAUDIO_HAS_ATOMIC && BR2_USE_WCHAR && BR2_TOOLCHAIN_HAS_THREADS && !BR2_STATIC_LIBS && BR2_USE_MMU)

This commit fixes that by propagating the dependency as it should have
been done.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>