MIPS: create .text sub-sections for assembler functions

Put all functions coded in assembly in sub-sections of
section .text. This allows the linker to garbage collect
unused assembly functions too.
Signed-off-by: NDaniel Schwierzeck <daniel.schwierzeck@gmail.com>

arch/mips/include/asm/asm.h

@@ -59,6 +59,7 @@ symbol:
 		.align	2;                              \
 		.type	symbol, @function;              \
 		.ent	symbol, 0;                      \
+		.section .text.symbol, "x";             \
 symbol:		.frame	sp, 0, ra
 
 /*
@@ -68,7 +69,8 @@ symbol:		.frame	sp, 0, ra
 		.globl	symbol;                         \
 		.align	2;                              \
 		.type	symbol, @function;              \
-		.ent	symbol, 0;                       \
+		.ent	symbol, 0;                      \
+		.section .text.symbol, "x";             \
 symbol:		.frame	sp, framesize, rpc
 
 /*