ALSA: portman2x4: remove unused portman_read_command,data functions

ALSA: portman2x4: remove unused portman_read_command,data functions

clang with W=1 reports
sound/drivers/portman2x4.c:185:18: error: unused function
  'portman_read_command' [-Werror,-Wunused-function]
static inline u8 portman_read_command(struct portman *pm)
                 ^
sound/drivers/portman2x4.c:195:18: error: unused function
  'portman_read_data' [-Werror,-Wunused-function]
static inline u8 portman_read_data(struct portman *pm)
                 ^
These static functions are not used, so remove them.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230318135229.1685266-1-trix@redhat.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>