arch: arm: mach-k3: common: Return a pointer after setting page table

In spl_dcache_enable after setting up page table, set gd->relocaddr
pointer to tlb_addr, to get next location to reserve memory. Align
tlb_addr with 64KB address.

Signed-off-by: Nikhil M Jain <n-jain1@ti.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>