ARM: kprobes: Fix emulation of Data-processing (immediate) instructions

Emulation of instructions like "ADD rd, rn, #<const>" would result in a
corrupted value for rd.
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>

arch/arm/kernel/kprobes-decode.c

@@ -1207,7 +1207,7 @@ space_cccc_001x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	 * *S (bit 20) updates condition codes
 	 * ADC/SBC/RSC reads the C flag
 	 */
-	insn &= 0xffff0fff;	/* Rd = r0 */
+	insn &= 0xfff00fff;	/* Rn = r0 and Rd = r0 */
 	asi->insn[0] = insn;
 
 	if ((insn & 0x0f900000) == 0x03100000) {