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>
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 0e12e0a..acf5e6f 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -355,7 +355,7 @@
  * the thread function, and r3 points to the exit function.
  */
 extern void kernel_thread_helper(void);
-asm(	".section .text\n"
+asm(	".pushsection .text\n"
 "	.align\n"
 "	.type	kernel_thread_helper, #function\n"
 "kernel_thread_helper:\n"
@@ -363,11 +363,11 @@
 "	mov	lr, r3\n"
 "	mov	pc, r2\n"
 "	.size	kernel_thread_helper, . - kernel_thread_helper\n"
-"	.previous");
+"	.popsection");
 
 #ifdef CONFIG_ARM_UNWIND
 extern void kernel_thread_exit(long code);
-asm(	".section .text\n"
+asm(	".pushsection .text\n"
 "	.align\n"
 "	.type	kernel_thread_exit, #function\n"
 "kernel_thread_exit:\n"
@@ -377,7 +377,7 @@
 "	nop\n"
 "	.fnend\n"
 "	.size	kernel_thread_exit, . - kernel_thread_exit\n"
-"	.previous");
+"	.popsection");
 #else
 #define kernel_thread_exit	do_exit
 #endif