ARM: fix build error in arch/arm/kernel/process.c

/tmp/ccJ3ssZW.s: Assembler messages:
/tmp/ccJ3ssZW.s:1952: Error: can't resolve `.text' {.text section} - `.LFB1077'

This is caused because:

	.section .data
	.section .text
	.section .text
	.previous

does not return us to the .text section, but the .data section; this
makes use of .previous dangerous if the ordering of previous sections
is not known.

Fix up the other users of .previous; .pushsection and .popsection are
a safer pairing to use than .section and .previous.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/ftrace.c

@@ -62,15 +62,15 @@ int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
 		"    movne  %0, #2    \n"
 		"3:\n"
 
-		".section .fixup, \"ax\"\n"
+		".pushsection .fixup, \"ax\"\n"
 		"4:  mov  %0, #1  \n"
 		"    b    3b      \n"
-		".previous\n"
+		".popsection\n"
 
-		".section __ex_table, \"a\"\n"
+		".pushsection __ex_table, \"a\"\n"
 		"    .long 1b, 4b \n"
 		"    .long 2b, 4b \n"
-		".previous\n"
+		".popsection\n"
 
 		: "=r"(err), "=r"(replaced)
 		: "r"(pc), "r"(new), "r"(old), "0"(err), "1"(replaced)