arch/powerpc: Remove unused function icp_native_cause_ipi_rm()

Remove icp_native_cause_ipi_rm() as it has no callers since
commit 53af3ba("KVM: PPC: Book3S HV: Allow guest exit path to have
MMU on")

Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250101134251.436679-1-gautam@linux.ibm.com

Author: Gautam Menghani

arch/powerpc/include/asm/xics.h

@@ -31,7 +31,6 @@
 #ifdef CONFIG_PPC_ICP_NATIVE
 extern int icp_native_init(void);
 extern void icp_native_flush_interrupt(void);
-extern void icp_native_cause_ipi_rm(int cpu);
 #else
 static inline int icp_native_init(void) { return -ENODEV; }
 #endif

arch/powerpc/sysdev/xics/icp-native.c

@@ -145,27 +145,6 @@ static void icp_native_cause_ipi(int cpu)
 	icp_native_set_qirr(cpu, IPI_PRIORITY);
 }
 
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
-void icp_native_cause_ipi_rm(int cpu)
-{
-	/*
-	 * Currently not used to send IPIs to another CPU
-	 * on the same core. Only caller is KVM real mode.
-	 * Need the physical address of the XICS to be
-	 * previously saved in kvm_hstate in the paca.
-	 */
-	void __iomem *xics_phys;
-
-	/*
-	 * Just like the cause_ipi functions, it is required to
-	 * include a full barrier before causing the IPI.
-	 */
-	xics_phys = paca_ptrs[cpu]->kvm_hstate.xics_phys;
-	mb();
-	__raw_rm_writeb(IPI_PRIORITY, xics_phys + XICS_MFRR);
-}
-#endif
-
 /*
  * Called when an interrupt is received on an off-line CPU to
  * clear the interrupt, so that the CPU can go back to nap mode.