mpc885_ads_defconfig is used by several CI robots.

A few functionnalities are specific to 8xx and are not covered
by other default configuration, so improve build test coverage
by adding them to mpc885_ads_defconfig.

8xx is the only platform supporting 16k page size in addition
to 4k page size. Considering that 4k page size is widely tested
by other configurations, lets make 16k pages the selection for
8xx, as it has demonstrated in the past to be a weakness.

CONFIG_PIN_TLB is specific to 8xx, select it as it mainly adds
code with removing much.

CONFIG_BDI_SWITCH is specific to PPC32 and adds codes.

CONFIG_PPC_PTDUMP has specific part for 8xx.

CONFIG_MODULES has specific handling for 8xx.

CONFIG_SMC_UCODE_PATCH is specific to 8xx for loading microcode.

CONFIG_PERF_EVENTS has specific parts for 8xx.

CONFIG_MATH_EMULATION is used by 8xx.

CONFIG_STRICT_KERNEL_RWX has specificities for 8xx.

CONFIG_VIRT_CPU_ACCOUNTING_NATIVE has specific parts for PPC32.

CONFIG_IPV6 has specificities for PPC32.

CONFIG_BPF_JIT has specificities for PPC32.

A few drivers are tightly linked to the 8xx:
- CONFIG_SPI_FSL_SPI
- CONFIG_CRYPTO_DEV_TALITOS
- CONFIG_8xxx_WDT
- CONFIG_8xx_GPIO
- CONFIG_PPC_EARLY_DEBUG_CPM
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2541e4e415505b27db8ccbb8977035c20e408ef4.1620405461.git.christophe.leroy@csgroup.eu