lib: Rename rsa-checksum.c to hash-checksum.c

rsa-checksum.c sontains the hash_calculate() implementations. Despite
the "rsa-" file prefix, this function is useful for other algorithms.

To prevent confusion, move this file to lib/, and rename it to
hash-checksum.c, to give it a more "generic" feel.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/Makefile b/tools/Makefile
index 62de7e6..e968b20 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -67,7 +67,7 @@
 		fdt_strerror.o fdt_empty_tree.o fdt_addresses.o fdt_overlay.o)
 
 RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := $(addprefix lib/rsa/, \
-					rsa-sign.o rsa-verify.o rsa-checksum.o \
+					rsa-sign.o rsa-verify.o \
 					rsa-mod-exp.o)
 
 AES_OBJS-$(CONFIG_FIT_CIPHER) := $(addprefix lib/aes/, \
@@ -106,6 +106,7 @@
 			socfpgaimage.o \
 			sunxi_egon.o \
 			lib/crc16.o \
+			lib/hash-checksum.o \
 			lib/sha1.o \
 			lib/sha256.o \
 			lib/sha512.o \