Fixed type mismatch for ioctl(BLKGETSIZE)

ioctl(BLKGETSIZE) expects unsigned long
(8 bytes on 64 bit environment).

This is fixing fails in android.os.storage.StorageManagerIntegrationTest
(in FrameworkCoreTests).

To verify, install FrameworksCoreTests.apk and do:

adb shell am instrument -r -w -e class android.os.storage.\
StorageManagerIntegrationTest#testMountSingleEncryptedObb \
com.android.frameworks.coretests/android.test.InstrumentationTestRunner

Change-Id: Ib6d5c7490c02521c93f107c35ad0aac49f6a3f1a
diff --git a/VoldUtil.h b/VoldUtil.h
index 469489a..5738382 100644
--- a/VoldUtil.h
+++ b/VoldUtil.h
@@ -22,7 +22,7 @@
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
 
 __BEGIN_DECLS
-  unsigned int get_blkdev_size(int fd);
+void get_blkdev_size(int fd, unsigned long* nr_sec);
 __END_DECLS
 
 #endif