util/crossgcc: Update mpc to 1.2.1

Change-Id: Ic1422464d0a95c9cba1c417aaa05e4f1fe799d26
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54048
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

util/crossgcc/buildgcc

@@ -34,7 +34,7 @@ THREADS=1
 # GCC toolchain version numbers
 GMP_VERSION=6.2.1
 MPFR_VERSION=4.1.0
-MPC_VERSION=1.2.0
+MPC_VERSION=1.2.1
 GCC_VERSION=8.3.0
 GCC_AUTOCONF_VERSION=2.69
 BINUTILS_VERSION=2.35.1