arch: arm64: Remove useless assembly code
arch: arm64: Remove useless assembly code

The content of the SCR_EL3 register is overwritten by a later
instruction. Also no need to route SError, IRQs and FIQs to EL3.

Signed-off-by: Carlo Caione <ca4506c8c654a4ccf75802e86b5d162c1e96f065@baylibre.com>

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