init/main.c: fix symbol shadows noise

The symbol 'call' is a static symbol used for initcall_debug.  This same
symbol name is used locally by a couple functions and produces the
following sparse warnings:

	warning: symbol 'call' shadows an earlier one

Fix this noise by renaming the local symbols.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>