tvheadend: Fix SPKVAR installation & SPK_DEPENDS

1. Migrate to using new STAGING_SPKVAR variable to fix SynoCommunity#4758
2. Also fix SPK_DEPENDS which got superseeded by ffmpeg instead
   of it being updated with added ffmpeg
3. Bump package version

spk/tvheadend/Makefile

@@ -4,7 +4,7 @@ SPK_GIT_HASH = eb59284
 SPK_GIT_DATE = 20210612
 SPK_VERS = $(SPK_SHORT_VERS).$(SPK_GIT_DATE)
 TVH_VERS = $(SPK_SHORT_VERS)~$(SPK_GIT_HASH)
-SPK_REV = 29
+SPK_REV = 30
 SPK_ICON = src/tvheadend.png
 DSM_UI_DIR = app
 
@@ -52,7 +52,7 @@ export FFMPEG_DIR = $(shell pwd)/../ffmpeg/work-$(ARCH)-$(TCVERSION)/install/var
 
 ifneq ($(wildcard $(FFMPEG_DIR)),)
 PRE_DEPEND_TARGET = tvheadend_pre_depend
-SPK_DEPENDS = "ffmpeg>4.1"
+SPK_DEPENDS := "$(SPK_DEPENDS):ffmpeg>4.1"
 endif
 
 include ../../mk/spksrc.spk.mk
@@ -77,8 +77,8 @@ tvheadend_pre_depend:
 	$(foreach lib,$(VAAPI_LIBS),ln -sfT $(FFMPEG_DIR)/lib/pkgconfig/$(lib) $(STAGING_INSTALL_PREFIX)/lib/pkgconfig/$(lib) ;)
 
 tvheadend_extra_install:
-	install -p -m 700 -d $(STAGING_DIR)/var/accesscontrol
-	install -p -m 700 -d $(STAGING_DIR)/var/passwd
+	install -p -m 700 -d $(STAGING_SPKVAR)/accesscontrol
+	install -p -m 700 -d $(STAGING_SPKVAR)/passwd
 	# The following filenames stem from an arbitrary (valid) combination created by TVH
-	install -m 640 src/accesscontrol.json $(STAGING_DIR)/var/accesscontrol/d80ccc09630261ffdcae1497a690acc8
-	install -m 640 src/passwd.json $(STAGING_DIR)/var/passwd/a927e30a755504f9784f23a4efac5109
+	install -m 640 src/accesscontrol.json $(STAGING_SPKVAR)/accesscontrol/d80ccc09630261ffdcae1497a690acc8
+	install -m 640 src/passwd.json $(STAGING_SPKVAR)/passwd/a927e30a755504f9784f23a4efac5109