fpga: Add support to load partial and compressed bitstreams

Added support to load partial and compressed bitstreams.
The partial bitstreams can be loaded using the below commands
Commands:
fpga loadp <dev> <addr> <size>
fpga loadbp <dev> <addr> <size>
The compressed and full bit streams can be loaded using the
old commands(fpga load and fpga loadb).

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
ARM: zynq: slcr: Fix incorrect commentary

Fix c&p error in zynq_slcr_devcfg_enable() commentary
and extending it with description according
to Zynq TRM also in zynq_slcr_devcfg_disable().

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
spi: zynq_qspi: Fix BAUD_RATE_DIV calculation

Correct the baud rate divisor calculation by looping
until baud_rate_val < 7 instead of 8 as 8 is an invalid
baud rate divisor.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>