powerpc/mm: Disable kcov for SLB routines

The kcov instrumentation inside SLB routines causes duplicate SLB
entries to be added resulting into SLB multihit machine checks.
Disable kcov instrumentation on slb.o

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/Makefile

@@ -52,3 +52,6 @@ obj-$(CONFIG_PPC_MEM_KEYS)	+= pkeys.o
 # This is necessary for booting with kcov enabled on book3e machines
 KCOV_INSTRUMENT_tlb_nohash.o := n
 KCOV_INSTRUMENT_fsl_booke_mmu.o := n
+
+# Instrumenting the SLB fault path can lead to duplicate SLB entries
+KCOV_INSTRUMENT_slb.o := n