mips/bcm77xx: remove legacy __cpuinit sections that crept in

We removed __cpuinit support (leaving no-op stubs) quite some time ago.
However a few more crept in as of commit 6ee1d934
("MIPS: BCM47XX: Detect more then 128 MiB of RAM (HIGHMEM)")

Since we want to clobber the stubs soon, get this removed now.

Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>