core/mmu v7: move code inside core_mmu_divide_block
core/mmu v7: move code inside core_mmu_divide_block

This change allocates the L2 table only once it is useful. This change
allows to eventually exit the function without freeing the L2 is
something fails before we are filling the L2 table content.

Signed-off-by: Etienne Carriere <f21bc5b8f3ea1962eb45af359f1abea6578cab94@linaro.org>
Acked-by: Jens Wiklander <7706914404370d7502c27a0eff493dcf491feb51@linaro.org>
Reviewed-by: Volodymyr Babchuk <07adff7e050dc3230ac0b7d9c296bbb62f4ecc95@gmaill.com>

pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os