docs: usb: fix malformed table

The tables are separated with tabs and spaces mixed together, leading
to malformation. Changed the characters all into spaces to solve this
issue.
Signed-off-by: Hu Haowen <src.res@email.cn>
Link: https://lore.kernel.org/r/20210805040146.121526-1-src.res@email.cnSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/usb/gadget-testing.rst

@@ -724,7 +724,7 @@ Function-specific configfs interface
 The function name to use when creating the function directory is "uac2".
 The uac2 function provides these attributes in its function directory:
 
-	=============== ====================================================
+	================ ====================================================
 	c_chmask         capture channel mask
 	c_srate          capture sampling rate
 	c_ssize          capture sample size (bytes)
@@ -745,7 +745,7 @@ The uac2 function provides these attributes in its function directory:
 	p_volume_res     playback volume control resolution (in 1/256 dB)
 	req_number       the number of pre-allocated request for both capture
 	                 and playback
-	=============== ====================================================
+	================ ====================================================
 
 The attributes have sane default values.
 
@@ -914,7 +914,7 @@ Function-specific configfs interface
 The function name to use when creating the function directory is "uac1".
 The uac1 function provides these attributes in its function directory:
 
-	========== ====================================================
+	================ ====================================================
 	c_chmask         capture channel mask
 	c_srate          capture sampling rate
 	c_ssize          capture sample size (bytes)
@@ -933,7 +933,7 @@ The uac1 function provides these attributes in its function directory:
 	p_volume_res     playback volume control resolution (in 1/256 dB)
 	req_number       the number of pre-allocated request for both capture
 	                 and playback
-	========== ====================================================
+	================ ====================================================
 
 The attributes have sane default values.