MIPS: allow building with kcov coverage

Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to MIPS config.
Disable instrumentation of vdso to avoid build failure.
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

arch/mips/Kconfig

@@ -87,6 +87,8 @@ config MIPS
 	select SYSCTL_EXCEPTION_TRACE
 	select VIRT_TO_BUS
 	select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
+	select ARCH_HAS_KCOV
+	select HAVE_GCC_PLUGINS
 
 menu "Machine selection"
 

arch/mips/vdso/Makefile

@@ -75,6 +75,7 @@ CFLAGS_REMOVE_vdso.o = -pg
 
 GCOV_PROFILE := n
 UBSAN_SANITIZE := n
+KCOV_INSTRUMENT := n
 
 #
 # Shared build commands.