hrcon: Migrate to CONFIG_TARGET_HRCON

Use the proper CONFIG_TARGET_HRCON Kconfig option to replace
the CONFIG_HRCON ad-hoc config option.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/include/gdsys_fpga.h b/include/gdsys_fpga.h
index db4424d..e9fb4b8 100644
--- a/include/gdsys_fpga.h
+++ b/include/gdsys_fpga.h
@@ -161,7 +161,7 @@
 };
 #endif
 
-#if defined(CONFIG_HRCON) || defined(CONFIG_STRIDER_CON_DP)
+#if defined(CONFIG_TARGET_HRCON) || defined(CONFIG_STRIDER_CON_DP)
 struct ihs_fpga {
 	u16 reflection_low;	/* 0x0000 */
 	u16 versions;		/* 0x0002 */