gdb: Remove MIPS NSIG patch

This bug was fixed in the libc:
https://sourceware.org/bugzilla/show_bug.cgi?id=14523
https://git.busybox.net/uClibc/commit/?id=2da958760f798224065508431787e3a83b7fe2ae
https://git.musl-libc.org/cgit/musl/commit/?id=7c440977db9444d7e6b1c3dcb1fdf4ee49ca4158

Link: https://github.com/openwrt/openwrt/pull/16665
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/devel/gdb/patches/001-gdb-pr14523-mips-signal-number.patch

@@ -1,16 +0,0 @@
-See http://sourceware.org/bugzilla/show_bug.cgi?id=14523
-
---- a/gdbsupport/signals.cc
-+++ b/gdbsupport/signals.cc
-@@ -347,6 +347,11 @@ gdb_signal_from_host (int hostsig)
-       else if (64 <= hostsig && hostsig <= 127)
- 	return (enum gdb_signal)
- 	  (hostsig - 64 + (int) GDB_SIGNAL_REALTIME_64);
-+      else if (hostsig == 128)
-+	/* Some platforms, such as Linux MIPS, have NSIG == 128, in which case
-+	   signal 128 is the highest realtime signal. There is no constant for
-+	   that though. */
-+	return GDB_SIGNAL_UNKNOWN;
-       else
- 	error (_("GDB bug: target.c (gdb_signal_from_host): "
- 	       "unrecognized real-time signal"));