util/crossgcc/.gitignore: Add cmake

Change-Id: I5ce346515f4468699396e214acfaa3b62f6d891d
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49115
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

util/crossgcc/.gitignore

@@ -1,6 +1,7 @@
 acpica-unix-*/
 binutils-*/
 build-*BINUTILS/
+build-*CMAKE/
 build-*EXPAT/
 build-*GCC/
 build-*GDB/
@@ -11,6 +12,7 @@ build-*MPFR/
 build-*PYTHON/
 build-*LVM/
 build-*IASL/
+cmake-*/
 expat-*/
 gcc-*/
 gdb-*/