Add mobi extensions to known mime types

Allow .prc/.mobi file extensions to be read as a separate
mobi mime type. This allows Android to open mobi files
with the correct mime type.

This in turn allows applications to set their intent filters
based on mime type when opening mobi files.

Test: CtsMimeMapTestCases
Change-Id: I2b8f80f019f930f888e8e50db8b4efee0f0d4035

mime/java-res/android.mime.types

@@ -63,6 +63,7 @@
 ?application/x-android-drm-fl fl
 ?application/x-flac flac
 ?application/x-font pcf
+?application/x-mobipocket-ebook prc mobi
 ?application/x-mpegurl m3u m3u8
 ?application/x-pem-file pem
 ?application/x-pkcs12 p12 pfx