char: xdevcfg: Ensure PCAP loopback is disabled

Some versions of the Zynq first stage boot loader enable PCAP loopback
during boot regardless of whether or not the boot image includes PL
configuration. This behavior only appears in certain boot modes (notably
QSPI boot). Attempting to configure the PL with the loopback bit set
will result in timeouts and will prevent successful configuration.

In order to avoid this problem, and to avoid dependency on the version
of the FSBL used to boot the system, ensure that the loopback enable bit
is cleared when loading the driver.

Signed-off-by: Rob Armstrong <ra@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
char: devcfg: Remove de-documented user-mode feature

This bit has become un-documented, as it is a bootrom only feature.
It is marked as "do no modify", so the driver should only set it as
part of a read-modify-write process.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
arm: zynq: remove Makefile.boot

Since we have converted zynq to multiplatform build,
Makefile.boot is not used anyway. Remove it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
ARM: zynq: use generic cpu idle function for wfi

use cpu_do_idle for entering the wfi mode.

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>