fastboot: Remove "bootloader-version" variable

As per [1], there is no such fastboot variable as "bootloader-version".
Only "version-bootloader" is supported. Let's reflect this and not
confuse users further.

[1] https://android.googlesource.com/platform/system/core/+/refs/tags/android-q-preview-4/fastboot/README.md

Fixes: 3aab70afc531d1 ("usb/gadget: add the fastboot gadget")
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
diff --git a/drivers/fastboot/fb_getvar.c b/drivers/fastboot/fb_getvar.c
index fd0823b..ebe5c8a 100644
--- a/drivers/fastboot/fb_getvar.c
+++ b/drivers/fastboot/fb_getvar.c
@@ -12,7 +12,7 @@
 #include <version.h>
 
 static void getvar_version(char *var_parameter, char *response);
-static void getvar_bootloader_version(char *var_parameter, char *response);
+static void getvar_version_bootloader(char *var_parameter, char *response);
 static void getvar_downloadsize(char *var_parameter, char *response);
 static void getvar_serialno(char *var_parameter, char *response);
 static void getvar_version_baseband(char *var_parameter, char *response);
@@ -38,11 +38,8 @@
 		.variable = "version",
 		.dispatch = getvar_version
 	}, {
-		.variable = "bootloader-version",
-		.dispatch = getvar_bootloader_version
-	}, {
 		.variable = "version-bootloader",
-		.dispatch = getvar_bootloader_version
+		.dispatch = getvar_version_bootloader
 	}, {
 		.variable = "downloadsize",
 		.dispatch = getvar_downloadsize
@@ -131,7 +128,7 @@
 	fastboot_okay(FASTBOOT_VERSION, response);
 }
 
-static void getvar_bootloader_version(char *var_parameter, char *response)
+static void getvar_version_bootloader(char *var_parameter, char *response)
 {
 	fastboot_okay(U_BOOT_VERSION, response);
 }