si_types.h: fix build with gcc 10

Drop service_t, p_service_t, transponder_t and p_transponder_t to avoid
the following build failure with gcc 10 (which defaults to -fno-common):

/home/giuliobenetti/autobuild/run/instance-3/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc -Wall -Wextra -Wno-comment -Wswitch-default -Wno-unused-parameter -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os   -lrt  -o w_scan atsc_psip_section.o countries.o descriptors.o diseqc.o dump-dvbscan.o dump-vdr.o dump-xine.o dump-mplayer.o dump-vlc-m3u.o dvbscan.o lnb.o parse-dvbscan.o satellites.o scan.o section.o tools.o emulate.o dump-xml.o iconv_codes.o char-coding.o  
/home/giuliobenetti/autobuild/run/instance-3/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/10.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: descriptors.o:(.bss+0x404): multiple definition of `p_transponder_t'; countries.o:(.bss+0x0): first defined here
/home/giuliobenetti/autobuild/run/instance-3/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/10.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: descriptors.o:(.bss+0x408): multiple definition of `transponder_t'; countries.o:(.bss+0x4): first defined here
/home/giuliobenetti/autobuild/run/instance-3/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/10.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: descriptors.o:(.bss+0x480): multiple definition of `p_service_t'; countries.o:(.bss+0x7c): first defined here
/home/giuliobenetti/autobuild/run/instance-3/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/10.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: descriptors.o:(.bss+0x484): multiple definition of `service_t'; countries.o:(.bss+0x80): first defined here

Fixes:
 - http://autobuild.buildroot.org/results/5640442cb4ba06bcbcf31540a64f5665862d39f7

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

diff -Nura w_scan-20170107.orig/si_types.h w_scan-20170107/si_types.h
--- w_scan-20170107.orig/si_types.h	2020-09-20 11:09:56.776963441 +0200
+++ w_scan-20170107/si_types.h	2020-09-20 11:13:13.149232478 +0200
@@ -114,7 +114,7 @@
   uint32_t logical_channel_number;
   uint8_t  running;
   void   * priv;
-} service_t, * p_service_t;
+};
 
 /*******************************************************************************
 /* transponder type.
@@ -201,7 +201,7 @@
   /*----------------------------*/
   char * network_name;
   network_change_t network_change;
-} __attribute__((packed))  transponder_t, * p_transponder_t;
+} __attribute__((packed));
 
 /*******************************************************************************
 /* satellite channel routing type.