MAINTAINERS: Remove Mohit Kumar (email bounces)

Email to Mohit Kumar <mohit.kumar@st.com> has been bouncing, so remove the
address from MAINTAINERS and add an entry in CREDITS.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/CREDITS b/CREDITS
index 843e176..6bb0d51 100644
--- a/CREDITS
+++ b/CREDITS
@@ -2045,6 +2045,10 @@
 S: Gurgaon, India
 S: Kuala Lumpur, Malaysia
 
+N: Mohit Kumar
+D: ST Microelectronics SPEAr13xx PCI host bridge driver
+D: Synopsys Designware PCI host bridge driver
+
 N: Gabor Kuti
 M: seasons@falcon.sch.bme.hu
 M: seasons@makosteszta.sote.hu