microblaze: Add internal base vectors reg

Configurable at CPU synthesis/instantiation.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Merge remote-tracking branch 'osl/pub/clock.devl' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/fdt-generic.devl' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/pcie.devl' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/target-arm.devl' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/workarounds.devl' into integration/01-05-13/10-49-53
buildbot automerge aggressive
Merge remote-tracking branch 'osl/edgar/upstreamed.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/arm-midr.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/device-tree-null-size.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/dtc-submod.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/i2c.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/microblaze-boot-entry.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/nand.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/pl330.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/qspi.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/stream.next' into integration/01-05-13/10-49-53
Merge remote-tracking branch 'osl/pub/uboot-ramdisk.next' into integration/01-05-13/10-49-53
buildbot automerge aggressive
buildbot automerge aggressive