aarch64 crti.o: fix alignment of _init/_fini

without explicit alignment directives, whether they end up at the
necessary alignment depends on linker/linking conditions. initially
reported as mold issue 1255.

crt/aarch64/crti.s

@@ -1,6 +1,7 @@
 .section .init
 .global _init
 .type _init,%function
+.align 2
 _init:
 	stp x29,x30,[sp,-16]!
 	mov x29,sp
@@ -8,6 +9,7 @@ _init:
 .section .fini
 .global _fini
 .type _fini,%function
+.align 2
 _fini:
 	stp x29,x30,[sp,-16]!
 	mov x29,sp