Hexagon: append eflags to unknown cpu model string

Hexagon: append eflags to unknown cpu model string

Running qemu-hexagon with a binary that was compiled for an arch version
unknown by qemu can produce a somewhat confusing message:

  qemu-hexagon: unable to find CPU model 'unknown'

Let's give a bit more info by appending the eflags so that the message
becomes:

  qemu-hexagon: unable to find CPU model 'unknown (0x69)'

Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Tested-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <8a8d013cc619b94fd4fb577ae6a8df26cedb972b.1683225804.git.quic_mathbern@quicinc.com>