powerpc: remove dead CONFIG_HVC_SCOM code

Commit c1fb6816fb1b78dd94b673b0fdaa9a7a16e97bd1 ("powerpc: Add
relocation on exception vector handlers") added two lines of code that
depend on the macro CONFIG_HVC_SCOM. That macro doesn't exist. Perhaps
it was intended to use CONFIG_PPC_SCOM here. But since
"maintence_interrupt" is a typo and there's nothing in arch/powerpc that
looks like maintenance_interrupt it seems best to just delete these
lines.

Signed-off-by: Paul Bolle <[e-mail]>
Acked-by: Michael Ellerman <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/kernel/exceptions-64s.S

···
 	. = 0x5500
 	b	denorm_exception_hv
 #endif
-#ifdef CONFIG_HVC_SCOM
-	STD_RELON_EXCEPTION_HV(0x5600, 0x1600, maintence_interrupt)
-	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0x1600)
-#endif /* CONFIG_HVC_SCOM */
 	STD_RELON_EXCEPTION_PSERIES(0x5700, 0x1700, altivec_assist)
 
 	/* Other future vectors */