ARM: mm: improve do_ldrd_abort macro

Improve the do_ldrd_abort macro code - firstly, it inefficiently checks
for the LDRD encoding by doing a multi-stage test of various bits.  This
can be simplified by generating a mask, bitmasking the instruction and
then comparing the result.

Secondly, we want to be able to test the result rather than branching
to do_DataAbort, so remove the branch at the end and rename the macro
to 'teq_ldrd' to reflect it's new usage.  teq_ldrd macro returns 'eq'
if the instruction was a LDRD.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/abort-ev5t.S b/arch/arm/mm/abort-ev5t.S
index a0908d4..c913031 100644
--- a/arch/arm/mm/abort-ev5t.S
+++ b/arch/arm/mm/abort-ev5t.S
@@ -22,7 +22,8 @@
 	do_thumb_abort fsr=r1, pc=r4, psr=r5, tmp=r3
 	ldreq	r3, [r4]			@ read aborted ARM instruction
 	bic	r1, r1, #1 << 11		@ clear bits 11 of FSR
-	do_ldrd_abort tmp=ip, insn=r3
+	teq_ldrd tmp=ip, insn=r3		@ insn was LDRD?
+	beq	do_DataAbort			@ yes
 	tst	r3, #1 << 20			@ check write
 	orreq	r1, r1, #1 << 11
 	b	do_DataAbort