ARM: imx6: drop .text.head section annotation from headsmp.S

The function v7_secondary_startup() works just fine in .text section, so
there is no need to have .text.head section annotation at all.  Drop it.
Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/headsmp.S

@@ -13,8 +13,6 @@
 #include <linux/linkage.h>
 #include <linux/init.h>
 
-	.section ".text.head", "ax"
-
 diag_reg_offset:
 	.word	g_diag_reg - .