udf: fix 3 signedness & 1 unitialized variable warnings

sparse generated:
fs/udf/inode.c:324:41: warning: incorrect type in argument 4 (different signedness)
fs/udf/inode.c:324:41:    expected long *<noident>
fs/udf/inode.c:324:41:    got unsigned long *<noident>

inode_getblk always set 4th argument to uint32_t value
3rd parameter of map_bh is sector_t (which is unsigned long or u64)
so convert phys value to sector_t

fs/udf/inode.c:1818:47: warning: incorrect type in argument 3 (different signedness)
fs/udf/inode.c:1818:47:    expected int *<noident>
fs/udf/inode.c:1818:47:    got unsigned int *<noident>
fs/udf/inode.c:1826:46: warning: incorrect type in argument 3 (different signedness)
fs/udf/inode.c:1826:46:    expected int *<noident>
fs/udf/inode.c:1826:46:    got unsigned int *<noident>

udf_get_filelongad and udf_get_shortad are called always for uint32_t
values (struct extent_position->offset), so it's safe to convert offset
parameter to uint32_t

gcc warned:
fs/udf/inode.c: In function 'udf_get_block':
fs/udf/inode.c:299: warning: 'phys' may be used uninitialized in this function
initialize it to 0 (if someday someone will break inode_getblk we will catch it immediately)

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Ben Fennema <bfennema@falcon.csc.calpoly.edu>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/udf/directory.c b/fs/udf/directory.c
index d8ceb44..be16d76 100644
--- a/fs/udf/directory.c
+++ b/fs/udf/directory.c
@@ -282,7 +282,7 @@
 }
 #endif
 
-short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, int *offset,
+short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
 			      int inc)
 {
 	short_ad *sa;
@@ -292,7 +292,7 @@
 		return NULL;
 	}
 
-	if ((*offset < 0) || ((*offset + sizeof(short_ad)) > maxoffset))
+	if ((*offset + sizeof(short_ad)) > maxoffset)
 		return NULL;
 	else {
 		sa = (short_ad *)ptr;
@@ -305,7 +305,7 @@
 	return sa;
 }
 
-long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, int *offset, int inc)
+long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
 {
 	long_ad *la;
 
@@ -314,7 +314,7 @@
 		return NULL;
 	}
 
-	if ((*offset < 0) || ((*offset + sizeof(long_ad)) > maxoffset))
+	if ((*offset + sizeof(long_ad)) > maxoffset)
 		return NULL;
 	else {
 		la = (long_ad *)ptr;