target/arm: report ARMv8-A FP support for AArch32 -cpu max

When we converted to using feature bits in 602f6e42cfbf we missed out
the fact (dp && arm_dc_feature(s, ARM_FEATURE_V8)) was supported for
-cpu max configurations. This caused a regression in the GCC test
suite. Fix this by setting the appropriate bits in mvfr1.FPHP to
report ARMv8-A with FP support (but not ARMv8.2-FP16).

Fixes: https://bugs.launchpad.net/qemu/+bug/1836078

Backports commit 45b1a243b81a7c9ae56235937280711dd9914ca7 from qemu

qemu/target/arm/cpu.c

@@ -1745,6 +1745,10 @@ static void arm_max_initfn(struct uc_struct *uc, Object *obj, void *opaque)
         t = FIELD_DP32(t, ID_ISAR6, SPECRES, 1);
         cpu->isar.id_isar6 = t;
 
+        t = cpu->isar.mvfr1;
+        t = FIELD_DP32(t, MVFR1, FPHP, 2);     /* v8.0 FP support */
+        cpu->isar.mvfr1 = t;
+
         t = cpu->isar.mvfr2;
         t = FIELD_DP32(t, MVFR2, SIMDMISC, 3); /* SIMD MaxNum */
         t = FIELD_DP32(t, MVFR2, FPMISC, 4);   /* FP MaxNum */