ath5k: fix uninitialized value use in ath5k_eeprom_read_turbo_modes()

ath5k: fix uninitialized value use in ath5k_eeprom_read_turbo_modes()

The `val' variable in ath5k_eeprom_read_turbo_modes() is used
uninitialized.  gcc 4.4.1 with -fno-inline-functions-called-once reports
it:

eeprom.c: In function 'ath5k_eeprom_read_turbo_modes':
eeprom.c:441: warning: 'val' may be used uninitialized in this function

Comparing the code to the Atheros HAL, it's clear that the split between
ath5k_eeprom_read_modes() and ath5k_eeprom_read_turbo_modes() was
incorrect.

The Atheros HAL reads both turbo and non-turbo data from EEPROM in one
function.  Some turbo mode parameters are derived from the same EEPROM
values as non-turbo parameters, just from different bits.

Merge ath5k_eeprom_read_turbo_modes() into ath5k_eeprom_read_modes() to
fix the warning.  The actual values and offsets have been cross-checked
against Atheros HAL.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>