FogBugz #188704: Fix QSPI read flag status sequence

Fixed the QSPI read status and read flag status register sequence.
To ensure reliable flash programming and erase, we would need
to read status register then follow by read flag status register.
While its not documented, its advised by Micron technical support.

Signed-off-by: Chin Liang See <clsee@altera.com>
FogBugz #189084: Enhance U-Boot to configure L2 address filter

Enhance the U-Boot to configure the L2 address filter. This
is to avoid the dependency of getting Preloader to configure it.

Signed-off-by: Chin Liang See <clsee@altera.com>
FogBugz #188622: Ensure BootROM works if SDMMC PWREN is used

If SDMMC PWREN is used, we need to ensure BootROM always
reconfigure IOCSR and pinmux after warm reset. This is to cater
the use case of board design which is using SDMMC PWREN pins.

Signed-off-by: Chin Liang See <clsee@altera.com>