MAINTAINERS: Add x86 unwinding entry

Create a new section for x86 unwinder maintenance.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/db2b764b735a9481df9f7717a3a1f75ba496fcc1.1650387176.git.jpoimboe@redhat.comSigned-off-by: Peter Zijlstra <peterz@infradead.org>

MAINTAINERS

@@ -21434,6 +21434,15 @@ F:	arch/x86/include/asm/uv/
 F:	arch/x86/kernel/apic/x2apic_uv_x.c
 F:	arch/x86/platform/uv/
 
+X86 STACK UNWINDING
+M:	Josh Poimboeuf <jpoimboe@redhat.com>
+M:	Peter Zijlstra <peterz@infradead.org>
+S:	Supported
+F:	arch/x86/include/asm/unwind*.h
+F:	arch/x86/kernel/dumpstack.c
+F:	arch/x86/kernel/stacktrace.c
+F:	arch/x86/kernel/unwind_*.c
+
 X86 VDSO
 M:	Andy Lutomirski <luto@kernel.org>
 L:	linux-kernel@vger.kernel.org