rtlwifi: rtl8723be: Replace local bit manipulation macros

This driver uses a set of local macros to manipulate the RX and TX
descriptors, which are all little-endian quantities. These macros
are replaced by the bitfield macros le32p_replace_bits() and
le32_get_bits(). In several places, the macros operated on an entire
32-bit word. In these cases, a direct read or replacement is used.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>