IVGCVSW-5919 Update android-nn-driver NnapiSupport.txt for 21.08

Signed-off-by: Matthew Sloyan <matthew.sloyan@arm.com>
Change-Id: I2006f1d696d155742227eed940d7d97ed9385a66
diff --git a/NnapiSupport.txt b/NnapiSupport.txt
index df95a23..2d2e77f 100644
--- a/NnapiSupport.txt
+++ b/NnapiSupport.txt
@@ -59,7 +59,7 @@
 NEG                          (FLOAT32, FLOAT16)
 NOT_EQUAL                    (BOOL8, FLOAT32, FLOAT16, INT32, QUANT8_ASYMM, QUANT8_ASYMM_SIGNED)
 PAD                          (FLOAT32, FLOAT16, QUANT8_ASYMM)
-PAD_V2                       (FLOAT32, FLOAT16, QUANT8_ASYMM)
+PAD_V2                       (FLOAT32, FLOAT16, QUANT8_ASYMM, QUANT8_ASYMM_SIGNED)
 PRELU                        (FLOAT32, FLOAT16, QUANT8_ASYMM, QUANT8_ASYMM_SIGNED)
 QUANTIZE                     (FLOAT32 (input only), QUANT8_ASYMM and QUANT8_ASYMM_SIGNED (output only))
 QUANTIZED_16BIT_LSTM         (QUANT8_ASYMM)