staging: rtl8192e: Change cpu_to_le16 to le16_to_cpu

Since the function auth_parse returns a u16, and
struct rtllib_authentication.status is defined as an __le16, it seems
that

	return cpu_to_le16(a->status);

should be

	return le16_to_cpu(a->status);

This change silences the following sparse warnings:
drivers/staging/rtl8192e/rtllib_softmac.c:1817:16:
 warning: cast from restricted __le16
drivers/staging/rtl8192e/rtllib_softmac.c:1817:16:
 warning: incorrect type in return expression (different base types)
drivers/staging/rtl8192e/rtllib_softmac.c:1817:16:
    expected unsigned short
drivers/staging/rtl8192e/rtllib_softmac.c:1817:16:
    got restricted __le16 [usertype] <noident>

Signed-off-by: Arno Tiemersma <arno.tiemersma@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>