fpga: kconfig: Rename SPL_FPGA_SUPPORT to SPL_FPGA

The patch does sed 's/SPL_FPGA_SUPPORT/SPL_FPGA/g' but also fixing Makefile
and zynqmp.c to simplify if/endif logic in zynqmp.c.

This change is mostly done to be able to use CONFIG_IS_ENABLED macro and
obj-$(CONFIG_$(SPL_)FPGA) in Makefile. For them symbols need to be in sync.

And removing one line from Topic Miami boards which is not needed because
symbol is not enabled via Kconfig.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index af8255a8..6e31d75 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -602,7 +602,7 @@
 	  Support for the underlying block device (e.g. MMC or USB) must be
 	  enabled separately.
 
-config SPL_FPGA_SUPPORT
+config SPL_FPGA
 	bool "Support FPGAs"
 	help
 	  Enable support for FPGAs in SPL. Field-programmable Gate Arrays