Staging: wlags49_h2: Fix Sparse Warning for Static Declarations in dhf.c

This patch fixes the following sparse warnings:
drivers/staging/wlags49_h2/dhf.c:109:6: warning: symbol 'signature' was not declared. Should it be static?
drivers/staging/wlags49_h2/dhf.c:126:25: warning: symbol 'mfi_sup' was not declared. Should it be static?
drivers/staging/wlags49_h2/dhf.c:127:25: warning: symbol 'cfi_sup' was not declared. Should it be static?
drivers/staging/wlags49_h2/dhf.c:142:17: warning: symbol 'ltv_info' was not declared. Should it be static?
drivers/staging/wlags49_h2/dhf.c:173:1: warning: symbol 'check_comp_fw' was not declared. Should it be static?

Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>