staging: vt6655:removed incorrect casting in hostap.c

This patch fixes the following type of sparse warnings:

drivers/staging/vt6655/hostap.c:733:42: warning: cast from restricted gfp_t
drivers/staging/vt6655/hostap.c:733:42: warning: incorrect type in argument 2 (different base types)
drivers/staging/vt6655/hostap.c:733:42:    expected restricted gfp_t [usertype] flags
drivers/staging/vt6655/hostap.c:733:42:    got int [signed] <noident>

Signed-off-by: Archana kumari <archanakumari959@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>