test/py: Drop u_boot_ prefix on test files

We know this is U-Boot so the prefix serves no purpose other than to
make things longer and harder to read. Drop it and rename the files.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # test_android / test_dfu
diff --git a/test/py/tests/test_sf.py b/test/py/tests/test_sf.py
index 9c3b892..5b4ba80 100644
--- a/test/py/tests/test_sf.py
+++ b/test/py/tests/test_sf.py
@@ -5,7 +5,7 @@
 import re
 import pytest
 import random
-import u_boot_utils
+import utils
 
 """
 Note: This test relies on boardenv_* containing configuration values to define
@@ -57,7 +57,7 @@
     """
 
     sf_params = {}
-    sf_params['ram_base'] = u_boot_utils.find_ram_base(ubman)
+    sf_params['ram_base'] = utils.find_ram_base(ubman)
 
     probe_id = env__sf_config.get('id', 0)
     speed = env__sf_config.get('speed', 0)
@@ -123,14 +123,14 @@
 
     cmd = 'mw.b %08x %02x %x' % (addr, pattern, count)
     ubman.run_command(cmd)
-    crc_pattern = u_boot_utils.crc32(ubman, addr, count)
+    crc_pattern = utils.crc32(ubman, addr, count)
     if crc_expected:
         assert crc_pattern != crc_expected
 
     cmd = 'sf read %08x %08x %x' % (addr, offset, count)
     response = ubman.run_command(cmd)
     assert 'Read: OK' in response, 'Read operation failed'
-    crc_readback = u_boot_utils.crc32(ubman, addr, count)
+    crc_readback = utils.crc32(ubman, addr, count)
     assert crc_pattern != crc_readback, 'sf read did not update RAM content.'
     if crc_expected:
         assert crc_readback == crc_expected
@@ -156,7 +156,7 @@
 
     cmd = 'mw.b %08x %02x %x' % (addr, pattern, count)
     ubman.run_command(cmd)
-    crc_pattern = u_boot_utils.crc32(ubman, addr, count)
+    crc_pattern = utils.crc32(ubman, addr, count)
 
     cmd = 'sf update %08x %08x %x' % (addr, offset, count)
     ubman.run_command(cmd)
@@ -201,7 +201,7 @@
 
     cmd = 'mw.b %08x ff %x' % (addr, count)
     ubman.run_command(cmd)
-    crc_ffs = u_boot_utils.crc32(ubman, addr, count)
+    crc_ffs = utils.crc32(ubman, addr, count)
 
     crc_read = sf_read(ubman, env__sf_config, sf_params)
     assert crc_ffs == crc_read, 'Unexpected CRC32 after erase operation.'