target/riscv: rvv-1.0: Call the correct RVF/RVD check function for widening fp/int...

target/riscv: rvv-1.0: Call the correct RVF/RVD check function for widening fp/int type-convert insns

vfwcvt.xu.f.v, vfwcvt.x.f.v, vfwcvt.rtz.xu.f.v and vfwcvt.rtz.x.f.v
convert single-width floating-point to double-width integer.
Therefore, should use require_rvf() to check whether RVF/RVD is enabled.

vfwcvt.f.xu.v, vfwcvt.f.x.v convert single-width integer to double-width
floating-point, and vfwcvt.f.f.v convert double-width floating-point to
single-width floating-point. Therefore, should use require_scale_rvf() to
check whether RVF/RVD is enabled.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220105022247.21131-3-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>