MIPS: assume at as source/dest of MSA copy/insert instructions

Assuming at ($1) as the source or destination register of copy or
insert instructions:

  - Simplifies the macros providing those instructions for toolchains
    without MSA support.

  - Avoids an unnecessary move instruction when at is used as the source
    or destination register anyway.

  - Is sufficient for the uses to be introduced in the kernel by a
    subsequent patch.

Note that due to a patch ordering snafu on my part this also fixes the
currently broken build with MSA support enabled. The build has been
broken since commit c9017757c5 "MIPS: init upper 64b of vector
registers when MSA is first used", which this patch should have
preceeded.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9161/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/asmmacro.h

@@ -227,35 +227,35 @@
 	.set	pop
 	.endm
 
-	.macro	copy_u_w	rd, ws, n
+	.macro	copy_u_w	ws, n
 	.set	push
 	.set	mips32r2
 	.set	msa
-	copy_u.w \rd, $w\ws[\n]
+	copy_u.w $1, $w\ws[\n]
 	.set	pop
 	.endm
 
-	.macro	copy_u_d	rd, ws, n
+	.macro	copy_u_d	ws, n
 	.set	push
 	.set	mips64r2
 	.set	msa
-	copy_u.d \rd, $w\ws[\n]
+	copy_u.d $1, $w\ws[\n]
 	.set	pop
 	.endm
 
-	.macro	insert_w	wd, n, rs
+	.macro	insert_w	wd, n
 	.set	push
 	.set	mips32r2
 	.set	msa
-	insert.w $w\wd[\n], \rs
+	insert.w $w\wd[\n], $1
 	.set	pop
 	.endm
 
-	.macro	insert_d	wd, n, rs
+	.macro	insert_d	wd, n
 	.set	push
 	.set	mips64r2
 	.set	msa
-	insert.d $w\wd[\n], \rs
+	insert.d $w\wd[\n], $1
 	.set	pop
 	.endm
 #else
@@ -320,40 +320,36 @@
 	.set	pop
 	.endm
 
-	.macro	copy_u_w	rd, ws, n
+	.macro	copy_u_w	ws, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UW_MSA_INSN | (\n << 16) | (\ws << 11)
-	move	\rd, $1
 	.set	pop
 	.endm
 
-	.macro	copy_u_d	rd, ws, n
+	.macro	copy_u_d	ws, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UD_MSA_INSN | (\n << 16) | (\ws << 11)
-	move	\rd, $1
 	.set	pop
 	.endm
 
-	.macro	insert_w	wd, n, rs
+	.macro	insert_w	wd, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	move	$1, \rs
 	.word	INSERT_W_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm
 
-	.macro	insert_d	wd, n, rs
+	.macro	insert_d	wd, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	move	$1, \rs
 	.word	INSERT_D_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm