sparc64: Fix section mis-match errors.

Fix all of the problems spotted by CONFIG_DEBUG_SECTION_MISMATCH under
arch/sparc during a 64-bit defconfig build.

They fall into two categorites:

1) of_device_id is marked as __initdata, and we can never do this
   since these objects sit in the device core data structures way
   past boot.  So even if a driver will never be reloaded, we have
   to keep the device ID table around.

   Mark such cases const instead.

2) The bootmem alloc/free handling code in mdesc.c was not fully
   marked __init as it should be, thus generating a reference
   to free_bootmem_late() (which is __init) from non-__init code.

Signed-off-by: David S. Miller <davem@davemloft.net>