microblaze: cache: improve icache Kconfig options

Replace CONFIG_ICACHE with a Kconfig option more limited in scope -
XILINX_MICROBLAZE0_USE_WIC. It should be enabled if the processor supports
the "wic" (Write to Instruction Cache) instruction. It will be used to
guard "wic" invocations in microblaze cache code.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20220531181435.3473549-6-ovpanait@gmail.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/board/xilinx/microblaze-generic/Kconfig b/board/xilinx/microblaze-generic/Kconfig
index b00ce6f..98b4814 100644
--- a/board/xilinx/microblaze-generic/Kconfig
+++ b/board/xilinx/microblaze-generic/Kconfig
@@ -74,4 +74,15 @@
 	bool
 	default XILINX_MICROBLAZE0_USE_WDC
 
+config XILINX_MICROBLAZE0_USE_WIC
+	bool "MicroBlaze wic instruction support"
+	default y
+	help
+	  Enable this option if the MicroBlaze processor is configured with
+	  support for the "wic" (Write to Instruction Cache) instruction.
+
+config SPL_XILINX_MICROBLAZE0_USE_WIC
+	bool
+	default XILINX_MICROBLAZE0_USE_WIC
+
 endif