avr32: Put memset in its own section

All C code is compiled with -ffunction-sections -fdata-sections.
Assembly functions should get their own sections as well so that
everything looks consistent.
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>

lib_avr32/memset.S

@@ -27,7 +27,7 @@
 	 *
 	 * Returns b in r12
 	 */
-	.text
+	.section .text.memset, "ax", @progbits
 
 	.global	memset
 	.type	memset, @function