ASoC: tas2781: check the validity of prm_no/cfg_no

commit f32c80d3 upstream.

Add additional checks for program/config numbers to avoid loading from
invalid addresses.

If prm_no/cfg_no is negative, skip uploading program/config.

The tas2781-hda driver caused a NULL pointer dereference after loading
module, and before first runtime_suspend.

the state was:
tas_priv->cur_conf = -1;
tas_priv->tasdevice[i].cur_conf = 0;
program = &(tas_fmw->programs[-1]);

BUG: kernel NULL pointer dereference, address: 0000000000000010
Call Trace:
 <TASK>
 ? __die+0x23/0x70
 ? page_fault_oops+0x171/0x4e0
 ? vprintk_emit+0x175/0x2b0
 ? exc_page_fault+0x7f/0x180
 ? asm_exc_page_fault+0x26/0x30
 ? tasdevice_load_block_kernel+0x21/0x310 [snd_soc_tas2781_fmwlib]
 tasdevice_select_tuningprm_cfg+0x268/0x3a0 [snd_soc_tas2781_fmwlib]
 tasdevice_tuning_switch+0x69/0x710 [snd_soc_tas2781_fmwlib]
 tas2781_hda_playback_hook+0xd4/0x110 [snd_hda_scodec_tas2781_i2c]

Fixes: 915f5ead

 ("ASoC: tas2781: firmware lib")
CC:  <stable@vger.kernel.org>
Signed-off-by: Gergo Koteles <soyer@irl.hu>
Link: https://msgid.link/r/523780155bfdca9bc0acd39efc79ed039454818d.1702591356.git.soyer@irl.hu
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>