staging: cxt1e1: Fix Sparse Warning for Static Declarations in linux.c

staging: cxt1e1: Fix Sparse Warning for Static Declarations in linux.c

This patch fixes the following sparse warnings:
drivers/staging/cxt1e1/linux.c:106:13: warning: symbol 'log_level_default' was not declared. Should it be static?
drivers/staging/cxt1e1/linux.c:110:13: warning: symbol 'max_mru_default' was not declared. Should it be static?
drivers/staging/cxt1e1/linux.c:255:1: warning: symbol 'c4_linux_interrupt' was not declared. Should it be static?
drivers/staging/cxt1e1/linux.c:265:1: warning: symbol 'c4_ebus_interrupt' was not declared. Should it be static?

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>