ACPICA: Remove useless mini-C library.

The mini-C library implementation is used by the embedded ACPICA users
other than Linux.  It was added to the kernel source to make it easier
to incorporate future ACPICA changes, but as it turns our we can avoid
carrying it thanks to some ACPICA release process tweaks, so remove
drivers/acpi/acpica/utclib.c from the kernel source tree.

[rjw: Modified the changelog slightly.]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>