target/arm/translate-a64:Remove redundant statement in disas_simd_two…

…_reg_misc_fp16()

Clang static code analyzer show warning:
target/arm/translate-a64.c:13007:5: warning: Value stored to 'rd' is never read
    rd = extract32(insn, 0, 5);
    ^    ~~~~~~~~~~~~~~~~~~~~~
target/arm/translate-a64.c:13008:5: warning: Value stored to 'rn' is never read
    rn = extract32(insn, 5, 5);
    ^    ~~~~~~~~~~~~~~~~~~~~~

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200827110311.164316-5-kuhn.chenqun@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

target/arm/translate-a64.c

@@ -13014,9 +13014,6 @@ static void disas_simd_two_reg_misc_fp16(DisasContext *s, uint32_t insn)
     fpop = deposit32(opcode, 5, 1, a);
     fpop = deposit32(fpop, 6, 1, u);
 
-    rd = extract32(insn, 0, 5);
-    rn = extract32(insn, 5, 5);
-
     switch (fpop) {
     case 0x1d: /* SCVTF */
     case 0x5d: /* UCVTF */