QcomModulePkg: Allocate gRXBuffer size to match requested size

Allocated fbd.gRxBuffer currently is 1MB which queued to
receive cmd from host is less than size of command requested
which is GetXfrSize() 16MB.

The command size buffer of more than 1MB can cause crash
on device, which is due to buffer overflow.

Change to allocate fbd.gRxBuffer equal to maximum requested
size.

Change-Id: I16c947412dc805c0ca7e364967c53120a824d3ad
1 file changed