ida: Start new test_ida module

Start transitioning the IDA tests into kernel space.  Framework heavily
cribbed from test_xarray.c.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8838d11..2fff661 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1827,6 +1827,9 @@
 	  This is intended to help people writing architecture-specific
 	  optimized versions.  If unsure, say N.
 
+config TEST_IDA
+	tristate "Perform selftest on IDA functions"
+
 config TEST_PARMAN
 	tristate "Perform selftest on priority array manager"
 	default n