AArch32: Fix SCTLR context initialization

AArch32: Fix SCTLR context initialization

This patch fixes a bug in context management library when writing
SCTLR register during context initialization. The write happened
prior to initialization of the register context pointer. This
resulted in the compiler optimizing the write sequence from the
final binary and hence SCTLR remains uninitialized when
entering normal world. The bug is fixed by doing the
initialization of the register context pointer earlier in the
sequence.

Change-Id: Ic7465593a74534046b79f40446ffa1165c52ed76