mmc: sdhci: Fix read-only detection with JMicron 388 chip

On HP laptops with JMicron 388 chip, the write-locked SD card isn't
detected correctly as read-only in many cases.  This is because the
PRESENT_STATE register becomes unsable just after plugging, and it
returns the WRITE_PROTECT bit wrongly at the first read.

This patch fixes the read-only detection by adding a new sdhci quirk
indicating to check the register more intensively with a relatively
long delay.

The patch is tested with 2.6.39-rc4 kernel.

Cc: Aries Lee <arieslee@jmicron.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Chris Ball <cjb@laptop.org>