m25p80: Fix QIOR/DIOR handling for Winbond

m25p80: Fix QIOR/DIOR handling for Winbond

Winbond also support continuous read mode, but as an opposite for other
flash type read mode clock cycles are included to dummy cycles number.
This path add proper handling of read mode byte and update needed
dummy cycles. QPI mode and dummy cycles configuration are not supported.

Signed-off-by: Marcin Krzeminski <marcin.krzeminski@nokia.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1467809036-6986-1-git-send-email-marcin.krzeminski@nokia.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>