linux-user: Report AArch64 FP16 support via hwcap bits

Set the appropriate Linux hwcap bits to tell the guest binary if we
have implemented half-precision floating point support.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>

linux-user/elfload.c

@@ -551,6 +551,8 @@ static uint32_t get_elf_hwcap(void)
     GET_FEATURE(ARM_FEATURE_V8_SM3, ARM_HWCAP_A64_SM3);
     GET_FEATURE(ARM_FEATURE_V8_SM4, ARM_HWCAP_A64_SM4);
     GET_FEATURE(ARM_FEATURE_V8_SHA512, ARM_HWCAP_A64_SHA512);
+    GET_FEATURE(ARM_FEATURE_V8_FP16,
+                ARM_HWCAP_A64_FPHP | ARM_HWCAP_A64_ASIMDHP);
 #undef GET_FEATURE
 
     return hwcaps;