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/lib/putuser.S b/arch/arm/lib/putuser.S
index 02fedbf..5a01a23 100644
--- a/arch/arm/lib/putuser.S
+++ b/arch/arm/lib/putuser.S
@@ -81,11 +81,11 @@
 	mov	pc, lr
 ENDPROC(__put_user_bad)
 
-.section __ex_table, "a"
+.pushsection __ex_table, "a"
 	.long	1b, __put_user_bad
 	.long	2b, __put_user_bad
 	.long	3b, __put_user_bad
 	.long	4b, __put_user_bad
 	.long	5b, __put_user_bad
 	.long	6b, __put_user_bad
-.previous
+.popsection