platform/x86: apple-gmux: Update apple_gmux_detect documentation

Commit fc83fbc80e1a ("platform/x86: apple-gmux: refactor gmux types")
neglected to update the documentation of apple_gmux_detect's arguments.
Update the documentation to reflect that commit's changes.

include/linux/apple-gmux.h:99: warning:
Function parameter or member 'type_ret' not described in 'apple_gmux_detect'
include/linux/apple-gmux.h:99: warning:
Excess function parameter 'indexed_ret' description in 'apple_gmux_detect'

Reported-by: Stephen Rothwell <[e-mail]>
Link: https://lore.kernel.org/lkml/[e-mail]/
Fixes: fc83fbc80e1a ("platform/x86: apple-gmux: refactor gmux types")
Signed-off-by: Orlando Chamberlain <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Hans de Goede <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>

include/linux/apple-gmux.h

···
  * apple_gmux_detect() - detect if gmux is built into the machine
  *
  * @pnp_dev:     Device to probe or NULL to use the first matching device
- * @indexed_ret: Returns (by reference) if the gmux is indexed or not
+ * @type_ret: Returns (by reference) the apple_gmux_type of the device
  *
  * Detect if a supported gmux device is present by actually probing it.
  * This avoids the false positives returned on some models by