[coreboot] [PATCH][superiotool] Quit probe_idregs_* early if chip_found is set

[David Hendricks]

Some chips do not require enter/exit sequences. This causes them to be
detected and printed multiple times in probe_idregs_* functions where a
simple series of enter --> probe/print --> exit calls are made.

This patch adds a simple check after each set of those calls to make the
functions quit after a chip is found.

Signed-off by: David Hendricks ([e-mail])