bash: add -fomit-frame-pointer to DEBUG_OPTIMIZATION for armv[45] with thumb enabled

bash: add -fomit-frame-pointer to DEBUG_OPTIMIZATION for armv[45] with thumb enabled

with thumb and debug enabled bash gets stuck forever when building for qemuarm.

bash/4.4.18-r0/build/builtins$ arm-webos-linux-gnueabi-gcc  -march=armv5te -mthumb -fstack-protector-strong   --sysroot=bash/4.4.18-r0/recipe-sysroot -c  -DHAVE_CONFIG_H -DSHELL  -I. -I..  -I../../bash-4.4.18 -I../../bash-4.4.18/include -I../../bash-4.4.18/lib -I../../bash-4.4.18/builtins    -O -fno-omit-frame-pointer -g -DNON_INTERACTIVE_LOGIN_SHELLS read.c

when -mthumb, -fstack-protector-strong, -fno-omit-frame-pointer appear
together, removing one of them is enough for successful build.

similar to:
http://lists.openembedded.org/pipermail/openembedded-core/2018-May/150654.html
but in this case the build gets stuck instead of failure

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>