fix(arm_fpga): halve number of PEs per core

When creating the Arm FPGA platform, we had plenty of memory available,
so assigned a generous four PEs per core for the potential CPU topology.
In reality we barely see implementations with two PEs per core, and
didn't have four at all so far.

With some design changes we now include more data per CPU type, and
since the Arm FPGA build supports many cores (and determines the correct
one at runtime), we run out of memory with certain build options.

Since we don't really need four PEs per core, just halve that number, to
reduce our memory footprint without sacrificing functionality.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Change-Id: Ieb37ccc9f362b10ff0ce038f72efca21512a71cb
diff --git a/plat/arm/board/arm_fpga/fpga_def.h b/plat/arm/board/arm_fpga/fpga_def.h
index 2884ea6..5e3a0a9 100644
--- a/plat/arm/board/arm_fpga/fpga_def.h
+++ b/plat/arm/board/arm_fpga/fpga_def.h
@@ -21,7 +21,7 @@
 
 #define FPGA_MAX_CLUSTER_COUNT			4
 #define FPGA_MAX_CPUS_PER_CLUSTER		8
-#define FPGA_MAX_PE_PER_CPU			4
+#define FPGA_MAX_PE_PER_CPU			2
 
 #define FPGA_PRIMARY_CPU			0x0
 /*******************************************************************************