disp: msm: sde: aggregate all register dump memory allocation

In current implementation, register dump memory is allocated
separately for each range and block. When register dumps are
added to minidump, this will generate around 32 minidump bin files.
Changes are made to allocate all the required register dump memory
once. When register dumps are added to minidump, this will generate
only one minidump file.

Change-Id: I04d4d8db559f21f862f8989d3dfcfa7d9aef6dc5
Signed-off-by: Andhavarapu Karthik <kartkart@codeaurora.org>