ARM: 7230/1: mmc: mmci: Fix PIO read for small SDIO packets

Corrects a bug in MMCI host driver which silently causes
small reads (< 4 bytes as only used in SDIO) from PL-18X to fail.

Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Fredrik Soderstedt <fredrik.soderstedt@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>