toolchain: gdb: Update to version 16.3

toolchain: gdb: Update to version 16.3

This is a corrective release over GDB 16.2, fixing the following issues:

   PR symtab/32309 ([gdb/symtab, fission] gdb/dwarf2/read.h:289: internal-error: version: Assertion `m_dwarf_version != 0' failed)
   PR corefiles/32441 (gdb segfaults when generating a core file if target_fileio_read_alloc fails)
   PR tui/32623 (TUI console window doesn't update while inferior is running)
   PR corefiles/32634 ([gdb/corefiles] segfault in gdb.arch/i386-biarch-core.exp)
   PR backtrace/32757 ("Assertion `stashed' failed" when inline frame #0 is duplicated)
   PR tdep/32770 ([gdb/tdep, i386] FAIL: gdb.reverse/recvmsg-reverse.exp: continue to breakpoint: marker2)
   PR gdb/32775 ([AArch64] gdbserver crashes on SVE/SME-enabled systems)
   PR record/32784 ([gdb/record, aarch64] Stack smashing detected in aarch64_record_asimd_load_store)
   PR tui/32797 (Escape sequences to only reset foreground or background color to default fail)
   PR gdb/32828 (gstack regression: missing file names and line numbers)

Link: https://github.com/openwrt/openwrt/pull/20543
Signed-off-by: Hauke Mehrtens <[email protected]>