pflash_cfi01: duplicate status byte from bits 23:16 for 32bit reads

pflash_cfi01: duplicate status byte from bits 23:16 for 32bit reads

The firmware commonly used with MIPS Malta boards (YAMON) reads the
status of the pflash with a 32bit memory access. On real hardware
this results in the status byte being mirrored in the upper 16 bits
of the read value. For example if the status byte is represented by
SS then the hardware reads 0x00SS00SS. The YAMON firmware compares the
status against 32bit values expecting the mirrored value and fails
without it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>