mdss: Work around S6E8AA5X01 bootloader mdss string change

* Hardcoded mdss string in the bootloader command line passed to the
  kernel causes boot to fail on kernels with screen drivers not
  programmed to accept the old/new string. Fix this by checking for the
  presence of either of both strings at boot and initialising the
  display if at least one of them matches.

 This is the commit message #2:

mdss: Copy new display string to vdd->panel_name buffer

    pick a48dd39ecc1 mdss: Workaround S6E8AA5X01 bootloader mdss string change
    s 800da849db1 mdss: Copy new display string to vdd->panel_name buffer