arm: socfpga: remove re-added ad-hoc reset code

arm: socfpga: remove re-added ad-hoc reset code

commit 2eac5ade78b0 ("arm: socfpga: implement proper peripheral reset")
has removed the call to 'reset_deassert_peripherals_handoff()' from
socfpga gen5 SPL since the reset driver now handles resets. However,
commit 5775c86aa48c ("ARM: socfpga: Disable bridges in SPL unless booting from FPGA")
has re-added this ad-hoc reset code, so that all peripherals were now
again enabled instead of letting the drivers enable them by request.

While at it, remove this function for gen5 as it should not be used.

Fixes: commit 5775c86aa48c ("ARM: socfpga: Disable bridges in SPL unless booting from FPGA")
Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>