staging: vt6656: Remove logically dead code

staging: vt6656: Remove logically dead code

In the start of the "vnt_rf_set_txpower" function the "power" variable
is set at most to VNT_RF_MAX_POWER (hex = 0x3f, dec = 63). Then, in the
switch statement there are four comparisons with the "power" variable
against AL7230_PWR_IDX_LEN (dec = 64), VT3226_PWR_IDX_LEN (dec = 64),
VT3342_PWR_IDX_LEN (dec = 64). Due to all the commented comparisons are
to check if the "power" variable is "greater than or equal" to 64, this
never happens. So, remove the logically dead code.

Also, remove all the defines that are no longer required.

Addresses-Coverity-ID: 1230228 ("Logically dead code")
Fixes: f53d9f12c51a ("staging: vt6656: rf.c additional power.")
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
Link: https://lore.kernel.org/r/20200510090950.7633-1-oscar.carter@gmx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>