kbuild: fix false section mismatch with ARCH=um build

Ignoring references to .init.text, .exit.text from the .plt section brought
the false positives down to two warnings for a defconfig build of ARCH=um
on x86_64.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 94047bc..a70f5dd 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -822,6 +822,7 @@
 		".pdr",
 		"__param",
 		".smp_locks",
+		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
 		NULL
 	};
 	/* Start of section names */
@@ -894,6 +895,7 @@
 		".eh_frame",
 		".stab",
 		".smp_locks",
+		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
 		NULL
 	};
 	/* Start of section names */