arm: arm11: allow unaligned memory access

The UEFI spec mandates that unaligned memory access should be enabled if
supported by the CPU architecture.

This patch implements the function unaligned_access() to set the enable
unaligned data support flag and to clear the aligned flag in the system
control register (SCTLR). It is called when UEFI related commands like
bootefi are invoked.

Reported-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Tested-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>