powerpc/8xx: do not select CONFIG_PPC_LIB_RHEAP

Since commit 0e6e01ff694ee ("CPM/QE: use genalloc to manage CPM/QE
muram"), rheap is not used anymore.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/Kconfig.cputype

@@ -33,7 +33,6 @@ config PPC_85xx
 config PPC_8xx
 	bool "Freescale 8xx"
 	select FSL_SOC
-	select PPC_LIB_RHEAP
 	select SYS_SUPPORTS_HUGETLBFS
 
 config 40x