[RFC v6 13/25] powerpc: Add missing ppc_md.nvram_size for CHRP and PowerMac

Add the nvram_size() function to those PowerPC platforms that don't already have one: CHRP and PowerMac. This means that the ppc_md.nvram_size() function can be used to implement arch_nvram_ops.get_size() Since we are addressing inconsistencies here, also rename chrp_nvram_read and

[RFC v6 13/25] powerpc: Add missing ppc_md.nvram_size for CHRP and PowerMac

Add the nvram_size() function to those PowerPC platforms that don't already have one: CHRP and PowerMac. This means that the ppc_md.nvram_size() function can be used to implement arch_nvram_ops.get_size() Since we are addressing inconsistencies here, also rename chrp_nvram_read and