rsi: Rename file rsi_91x_pkt.c to rsi_91x_hal.c

The file rsi_91x_hal.c is going to contain device specific code i.e new
firmware loading method for RS9113 chipset. As the file rsi_91x_pkt.c
contains code to prepare device specific descriptors for transmit packet,
this file is renamed to rsi_91x_hal.c which is more relevant as per it's
functionality.

Signed-off-by: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Signed-off-by: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>