xtensa: improve vmlinux.lds.S sed post-processing

Current sed script makes assumptions about the structure of rules that
group .text sections in the vmlinux linker script. These assumptions
get broken occasionally, e.g.: 779c88c9 "ARM: 8321/1: asm-generic:
introduce.text.fixup input section", or 9bebe9e5 "kbuild: Fix
.text.unlikely placement".

Rewrite sed rules so that they don't depend on number/arrangement of text
sections in *(...) blocks.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/Makefile

@@ -28,10 +28,11 @@ AFLAGS_head.o += -mtext-section-literals
 #
 # Replicate rules in scripts/Makefile.build
 
-sed-y = -e 's/\*(\(\.[a-z]*it\|\.ref\|\)\.text)/*(\1.literal \1.text)/g' \
-	-e 's/\.text\.unlikely/.literal.unlikely .text.unlikely/g'	 \
-	-e 's/\*(\(\.text .*\))/*(.literal \1)/g'			 \
-	-e 's/\*(\(\.text\.[a-z]*\))/*(\1.literal \1)/g'
+sed-y = -e ':a; s/\*(\([^)]*\)\.text\.unlikely/*(\1.literal.unlikely .{text}.unlikely/; ta; ' \
+	-e ':b; s/\*(\([^)]*\)\.text\(\.[a-z]*\)/*(\1.{text}\2.literal .{text}\2/; tb; ' \
+	-e ':c; s/\*(\([^)]*\)\(\.[a-z]*it\|\.ref\)\.text/*(\1\2.literal \2.{text}/; tc; ' \
+	-e ':d; s/\*(\([^)]\+ \|\)\.text/*(\1.literal .{text}/; td; ' \
+	-e 's/\.{text}/.text/g'
 
 quiet_cmd__cpp_lds_S = LDS     $@
 cmd__cpp_lds_S = $(CPP) $(cpp_flags) -P -C -Uxtensa -D__ASSEMBLY__ $<    \