checkpatch.pl: Ignore mdelay instead of udelay

Whereas in Linux, on ARM there is the notion of delay operations and
mdelay and udelay are not the same, here we just have udelay and mdelay
is a trivial wrapper. Tell checkpatch to not complain here.

Reported-by: Bhimeswararao Matsa <bhimeswararao.matsa@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

.checkpatch.conf

@@ -19,6 +19,9 @@
 # Not Linux, so we don't recommend usleep_range() over udelay()
 --ignore USLEEP_RANGE
 
+# We also do not have a functionally different mdelay() and udelay()
+--ignore LONG_UDELAY
+
 # Ignore networking block comment style
 --ignore NETWORKING_BLOCK_COMMENT_STYLE