lrdp-v2: Fix some symbol loading issues on ARM-32 platforms

1) When lrdp-v2 is parsing RAM dumps generated on ARM-32 platforms,
   the Trace32 startup script will not contain any instructions
   to enable MMU support, which causes Linux kernel symbol loading
   failure on some newer Trace32 simulators.

   Add Trace32 startup instruction to set bit 0 of P15:0x1 if
   lrdp-v2 detects MMU support within the RAM dump.

2) Use task.symbol.loadmod instead of data.load.elf to load all
   the kernel moduels' symbols to avoid symbol loading failures.

Change-Id: Ibae79e3c80279788d7cccd28080d2cecd5432a4b