target/i386: Correct the warning message of Intel PT

target/i386: Correct the warning message of Intel PT

The CPUID level need to be set to 0x14 manually on old
machine-type if Intel PT is enabled in guest. E.g. the
CPUID[0].EAX(level)=7 and CPUID[7].EBX[25](intel-pt)=1 when the
Qemu with "-machine pc-i440fx-3.1 -cpu qemu64,+intel-pt" parameter.

This patch corrects the warning message of the previous
submission(ddc2fc9).

Signed-off-by: Luwei Kang <[email protected]>
Message-Id: <1593499113[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>