arm: socfpga: Add command to control HPS-FPGA bridges

arm: socfpga: Add command to control HPS-FPGA bridges

Add command to enable and disable the bridges between HPS and FPGA.

This patch does have a checkpatch issue with the assembler portion,
checkpatch correctly complains that there should be no whitespace
before quoted newline. I do not agree that fixing this specific
checkpatch issue will improve the readability, thus this one is not
addressed.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Marek Vasut <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Albert Aribaud <[email protected]>
Cc: Wolfgang Denk <[email protected]>