x86 instruction decoder bug: ficompl (%rbx)

[Ilya Maximets]

Hi.  While building the latest net tree on commit:

  0c7a5ba011d3 ("Merge branch 'mptcp-misc-fixes-for-v7-1-rc2'")

The instruction decoder reports the following failure:

arch/x86/tools/insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this.
arch/x86/tools/insn_decoder_test: warning: ffffffff81287b1e:    9b da 1b                ficompl (%rbx)
arch/x86/tools/insn_decoder_test: warning: objdump says 3 bytes, but insn_get_length() says 1

On a quick look I didn't find reports for this on the list, so reporting
it myself.  Can send a config or run some commands on a binary if needed.

Best regards, Ilya Maximets.