utils/genrandconfig: fix matching for a few lines

The matching in genrandconfig is idiomatically done by matching whole
lines, i.e. with the terminating \n but a few places are missing that.

Those are only matching against '=y', a boolean symbol, so it is in
practice not causing any issue. Still, for consistency, fix those.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

utils/genrandconfig

@@ -267,12 +267,12 @@ async def fixup_config(sysinfo, configfile):
        BR2_TOOLCHAIN_EXTERNAL_URL + 'mipsel-ctng-linux-uclibc.tar.xz"\n' in configlines:
         return False
     # No C library for internal toolchain
-    if 'BR2_TOOLCHAIN_BUILDROOT_NONE=y' in configlines:
+    if 'BR2_TOOLCHAIN_BUILDROOT_NONE=y\n' in configlines:
         return False
     # Xtensa custom cores require an overlay file with internal
     # toolchains
-    if 'BR2_XTENSA_CUSTOM=y' in configlines and \
-       'BR2_TOOLCHAIN_BUILDROOT=y' in configlines:
+    if 'BR2_XTENSA_CUSTOM=y\n' in configlines and \
+       'BR2_TOOLCHAIN_BUILDROOT=y\n' in configlines:
         return False
 
     if 'BR2_TOOLCHAIN_BARE_METAL_BUILDROOT=y\n' in configlines: